This is an example page. It’s different from a blog post because it will stay in one place and will show up in your site navigation (in most themes). Most people start with an About page that introduces them to potential site visitors. It might say something like this:

„Muzyka przychodzi do mnie łatwiej niż słowa”. – Ludwig Van Beethoven

…or something like this:

„Muzyka nie jest w nutach, ale w ciszy pomiędzy”. – Wolfgang Amadeusz Mozart

As a new WordPress user, you should go to your dashboard to delete this page and create new pages for your content. Have fun!