I explain it in different words:
The "Dice Server Section" is needed to get dice results from the server by email. It is totally unrelated to the question whether you Play by Forum or Play by Email. With these settings you can be sure that whatever dice results are sent by email to you and your opponent.
With those emails you can compare the dice results with what TripleA reports in the game (history) and thus you can be sure that your opponent did not cheat.
With Play By Forum you play using a forum as communication platform. You post your moves and your savegames in public, visible to all who access the forum.
With Play By Email you play hidden from the public, as you exchange game details only with your opponent. In the respective settings you will enter the details of your email account depending on your email provider.
Again this is totally unrelated to the dice server.
So in future games you fill in
- dice server settings and Play By Forum settings
- dice server settings and Play By Email settings.
Of course when you Play by Forum you don't need any Play By Email settings and vice versa.
But you always need the Dice Server settings plus either of them.
In case you are running different games at the same time you should verify that the settings represent the game you have just loaded. Usually the player setting up the game is in charge of correctly including the details. If everything has been set up correctly, you will get the correct details when loading the savegames. But better doublecheck to be sure!
Does that help?