@Ozymandiaswept
Hi Ozzy
Stick with us 
Some of the stuff doesn't work right now. This is how @victoryfirst taught me to do it and I have done the same ever sense. 2-3 years now and it works for me. I'm on ubuntu fwiw but everyone else on windows. Idk if you on mac will bring in ubernaut but it should work regardless.
this should show you what to do pretty much. disregard the clutter 
https://forums.triplea-game.org/topic/4376/playbyforum-first-utrecht
but you start pbem

make sure both emails registered to the Dice server hit register takes you here https://dice.triplea-game.org/
Ignore all the other bullshit and fire up a game 
So select game do the email shit make sure both emails registered and o h yea hit "test server" only need to do it once at game start, then you good to go.
Most people do a test turn in local mode then hit PBEM or Forum, they're basically interchangeable and do their final turn in pbem.

It'll say "Dice Server On "bottom right. When your turn is done you hit "Turn Summary" then ctrla ctrlc

Then save game ctrls
post the turn sumarry and saved game to your opponent at your game thread, we create a Game Thread here https://forums.triplea-game.org/category/45/play-by-forum
or you can send emails to each other
Edit
ask if you get stuck. I struggled hard trying to figure it out first time fwiw lol
Then @victoryfirst clued me in 