MyBB Community Forums

I'm changing my hosting. I need to save everything. I know how to save database. But how can i save all messages and the structure of my forum? What actions should i do?

i will be very thankful for help!

You have to download all files from your webspace and create a dump of your database. The database contains everything like users, posts, forums,...
You can use phpMyAdmin to create such a backup. Here you can find a tutorial.