DNS and .htaccess file - how to set up domain-hosting connection

[Freecoolin]

Hi,
I've got no experience with setting up the domain-hosting connection, so I'd like to ask you for help.
So far, I've understood, that I need to set hosting server's IP on the domain administration side, and that's what seems to work now. The domain is now redirected to the mainpage of my hostingprovider's server. But what I have to write into the .htaccess file to define what username and its subfolder the domain should go on?

I've got mydomain.com and hosting like username.hostingserver.com with only access to the html folder on ftp. I've already found solution for redirection within the hosting server (from username.hostingserver.com to username.hostingserver.com/prestashop) using the .htaccess file, but what next?

Please help me! :red: