step 1: go to
http://game.dom3minions.com/bin/blitz_chk.cgi
this is the status page. Note a game you would like to join, write down the port number next to the game. You might want to book mark the page
step 2. Open dominions, use the "create pretender" option under "game tools" -Make sure you set a password on the pretender
step 3. go to network options and connect to a domionion's server. Type in "game.dom3minions.com" hit enter. Type in your port number that you wrote down from step one.
step 4. you will be given a list of nations in that era, the ones that you have created pretender gods for will be highlighted. click on the nation to take control of it. You will get a message saying "Nation X is now human controlled" or something.
step 5. Finally if you are the last player to enter (ie the second in case of a duel.) then click start game, but if you are the first player to enter click "disconnect"
That is it, not as complicated as I made it sound.