I have found a very nice Tutorial for installation of phpBB3 for any domain.
phpBB is a free flat-forum bulletin board software solution that can be used to stay in touch with a group of people or can power your entire website.
phpBB3 installation include two parts
A) Database configuration.
B) phpBB3 installation.
1) Create Database
2) Create Database username
3) Database Password
4) Grant Proper Permissions to the users