transfer database

You just need to dump your database and reimport it to your new server.
PhpMyAdmin is your friend !

If you have attached files or documents, it will be a bit more complex : you'll have to copy them to new server.

On new server, be sure to install same version as the old.
Update you parameters.php file with parameters of new server (connection to db, files).
After migration, check all parameters in Global parameters.