Flarum isn't designed to run on shared hosting at this developing stage. You can try to install and run it, but... maybe you will find limitations.
Anyway isn't impossible install into shared hosting, but it requires some work. I did it sometimes mirroring a local dev flarum install into shared hosting (with some config.php changes) and everything works. But... do this will be your choice.
Flarum aslo have more reasons to be chosen over NodeBB or Discourse, but that is another history.