Are there some resources that I can consult to continue to develop my OS if until now I have followed the tutorial https://os.phil-opp.com/ ?

At the moment I just finished reading the code of post 11 "allocator design" and since post 12 is part of a section still not completed I decided not to follow it. So my code is currently like post 11. Now I'd like to start developing my OS to add new features, like a file system, and I need to add functionality based on the standard library even though at the moment the whole project is in one cargo no_std. How can I do this?