vulcano If you search this forum, you’ll find various tutorials. The short answer is, as long as the shared hosting provider is decent and offers SSH access, and ideally allows you to create folders one level below the public folder, you just follow the normal install instructions in the docs.
I also posted this a while back. I do not know if it’s still 100% accurate: https://discuss.flarum.org/d/19536-shared-hosting-installation-one-way
If you run into issues, just start a new support discussion and someone will probably help you troubleshoot. You need to at least know or learn some command line basics. Of course, I hear there’s other ways too even without SSH access. But, I don’t have any experience with those ways.