Two Major Site building options

As you saw previously, your Hostgator account includes a free site building program, and if the kind of site that you want to build happens to match what Hostgator are able to offer, then by all means go ahead and use their program.
Unfortunately however, it is almost certain that the type of site that you can build using the site builder that they offer is not going to generate the kind of website that you want to build.

After all, you are going to create a site that is focused on providing boxer dog training information whilst promoting a dog food related information product from that site.
Consequently, the first thing to consider is, what are you going to feature on your site apart from details of the affiliate product that you are promoting?
The answer to the question is, you are going to provide your visitors with information about dogs and dog training. Even more specifically, the majority of the content materials (i.e. information) on offer are going to focus on providing information that relates to training boxer dogs.

Thus, the type of site that you can create using the free Hostgator site builder program is probably not going to be particularly well-suited to what you want to do. You therefore have two choices of how you create your site.

Option one is to do things the 'traditional' way by building your site using HTML. This may sound as if it might be complex or difficult, but in reality, it is not.
If you have no experience of using HTML, it is not particularly difficult to build a site in this way because there are plenty of sites that provide free information about how to use HTML. Simply run a Google search for 'HTML tutorials' and you will find plenty of sites like this one where you can learn everything you need to know about HTML scripting.

Using the information from HTML tutorial sites like these, you should be able to create a simple web site pretty much as you want it to be, but it is not necessarily going to be a quick or easy process.

In order to do so however, it is definitely going to be easier to use a WYSIWYG ('what you see is what you get') site editor as an editor of this nature makes it far easier to see what you are doing as you are doing it.
Download the excellent (and completely free) NVU WYSIWYG site editor so that you can use it to build your HTML site quickly and easily.
Another HTML option is to start from a site template of the kind that can be downloaded free from OSWD or Free Web Templates. There are plenty of free templates available on the net and if you can find anything that appears suitable for the kind of site you want to build, using a template makes a great deal of sense.
Doing so obviously cuts down the amount of time and effort you need to expend on creating your website which is an important consideration. It is not until your site is finished and published that you can start to earn money, hence getting to that situation as quickly as possible is definitely something to aim for.
The only problem with the majority of free templates that are available on the net is that most of them are not really suited to online marketing sites. Consequently, starting from a template could mean that you would have to do so much work to modify it to make it 'match' your requirements that it might have been quicker and easier to start from scratch in the first place.
On the other hand, if you want a site that is perfectly matched to your own requirements, one that looks and does exactly what you want it to do, then creating your site using HTML should probably be your favored option. However, in this case, you will almost inevitably have to start from scratch, because using a site builder or a template is unlikely to come anywhere near what you want.
As previously suggested, creating a site using HTML can be a slow and relatively time-consuming process, particularly if you are learning how to code in HTML as you are going along.
For this reason, I would or most certainly recommend an alternative non-HTML site building option mainly because this alternative method is quick, easy and creates superbly effective websites.
The alternative that I would recommend, particularly to an online marketing beginner, is WordPress. This is a site building resource that was originally a blogging platform which has developed over the past two or three years to such an extent that it is now a highly effective (and extremely simple) site building tool.
Using this particular site building resource, even the greenest beginner can create a website within an hour or so in a 'worst-case scenario'. It should in fact be far quicker and easier than this.
To install WordPress on BoxerDogTrainingExpert.com, you have two choices.
The first option is to download the program from WordPress.org before installing it manually by following what the site calls the 'famous 5-minute installation'. Whilst I would suspect that the first time you are installing it, it will take a little longer than five minutes, it should nevertheless take no more than an hour to install and activate the site from beginning to end.
The alternative installation method does however genuinely take less than five minutes. Open the cPanel of your Hostgator account and look for the icon for 'Fantastico' or 'Fantastico De Luxe' near the bottom of the page under 'Software/Services':

'Fantastico' is a suite of programs that are already pre-installed on your site, ready to be activated whenever you decide that you want to start using that particular program. One of the programs that is included in the 'Fantastico' suite is WordPress. All that you need to do to prompt program activation you need to do is click on the WordPress link in the program list:

And then follow the step by step installation instructions. The first thing you need to do is click on the 'New Installation' icon (on the next page) that will transfer you to the main installation information page as shown below:

At the top of the page (1) will be the main domain name, below which you have the option of choosing a sub-directory of your site in which to install WordPress (2). However, because in this case, you want to install the software on the main BoxerDogTrainingExpert.com site, you would leave this box empty.
Next, you need to create an Administration username and password (3 and 4), after which you move onto the 'Base configuration'. The 'Admin nickname' that you choose for yourself (5) is the name that will appear as the author every time you add new information or content to your site, with the e-mail address (6) being the one to which any queries or comments that are submitted to your site by e-mail.
Next, you give the site a name (7) and a 'byline' that will appear underneath that name at the top of your WordPress page (8). Finally, click the 'Install WordPress' button (9) and that is the installation essentially complete. Using the information from the previous screen shot, you now have a site that looks something like this:

It is plain and basically little more than functional but at least you have a site that is live and published on the net.
The next step is to change the appearance of your site by finding and installing a new site template - known in 'WordPress-speak' as a theme - to make the site look more relevant to your subject matter.