new to this - what is backlinks in seo?

Not every link counts the same way, either. Links marked nofollow, sponsored or ugc tell Google not to treat them as an endorsement - it treats that as a hint these days, but they mostly don't move anything. Social profiles and blog comments are nearly all like that, which is why spamming them does nothing. You can see the links you actually have in Search Console under Links.

a link from someone else's site to yours. search engines treat them a bit like votes, except the votes are weighted - one link from a relevant, trusted site in your field is worth more than a hundred from random directories. the beginner trap is buying them in bulk. don't.