I've been trying to get better SEO for a while. One of the tools I've been trying has suggested,

You must also build backlinks to your site's internal pages to help Google™ bots crawl and index your web pages.

There are links on the front page to other pages in the site. None of the information I can find really explains what those links actually are, what they look like in a page.

If it helps to answer the question, I do have an updated sitemap thats updated about once a week, it gets resubmitted at least twice a month. The urls in the site are friendly urls.