Noob SEO Site structure question

So this is probably basic to most but its actually confusing me. In the guides im reading, its saying to have your homepage as you main keyword. Does that mean there is no other option other than to have the main keyword in my domain name?. As an example il use Alex beckers source wave site. When you go to his homepage,the url is source-wave.com . How is he supposed to be targeting anything to do with seo if the keywords are not in the url for that page?.Id understand if it was ranking like this source-wave.com/seo-for-beginners. Its just doing the onpage seo on a homepage im not understanding. Sorry if iv not explained this great. Basically, is the only way i can get keyword into the url of the homepage by getting it in the domain name?

First question - Your homepage must target a certain keyword?

Yes and No - Depending on your onsite optimization.. You can always create a page for to target a certain keyword. Personally, I dont use static homepage for my websites.. I always use dynamic content on the homepage. I just add new article to target my long tail keywords.

You certainly don't have to have the keyword in your domain name. Having an EMD is just an added bonus.

If you want source-wave.com to rank for "seo for beginners", You should add those keywords to the homepage title and H1/H2/H3 tags and link the homepage(source-wave.com) from your sub-pages with "seo for beginners" as anchor text. You should do the same for the new backlinks. The homepage will now rank for "seo for beginners" as well. Hope this answers your question.

Your domain name doesn't have to be the same as the title of your homepage. Look at GoDaddy. Title of their homepage is "Domain Names | The World's Largest Domain Name Registrar"

They're clearly targeting the keyword "Domain Names" which is why it's at the beginning of their SEO homepage title. Their homepage offers search of domain names right away. Obviously they're a well-known brand and can get away with a random name like "Godaddy" because they've branded / advertised it well over the years.

I think that as beginners without any authority in a certain niche, it's a good idea to start off with an exact match domain with your keyword like findadomain.com or whatever. That's probably why you see that advice everywhere.

Hope that helps!!

The idea is for the general subject in it's most broadest form to be targeted by the homepage, then use sub categories and filter down that way:

blahblahseo*com/link-building/tiered-links

Most of the time, the homepage also has the most links pointing to it, therefore makes it the most powerful page, and the fact that usually the broad term is hardest/most competitive to rank for, means that it often works more effectively.

Partial match domains are great to rank efficiently, branded (as in OP example) take more links to rank for the same terms that partial matches do.