Backlinks are other sites that link to your website. So imagine you write and post an article about a certain topic. If another source is writing about something similar, and they believe your article is helpful to their readers, they will add a link to your article in their post. In the eyes of a search engine, that other website is saying that you are a credible source on the topic. The higher the domain authority of the source that links to you, the more your own page will benefit.
Yes, backlinks will help you rank your content. But only if they are quality backlinks. Spammy black hat backlinks will actually hurt your sites rank.