The GUI is rather complicated at the moment...

Here is my question:
I don't want to play the NATO campaign first, I want to start achieving some victories for the communistic motherland!

Is that possible?

What is badly done too is that you have to spend your Command Stars in some OTAN units, if you want to play better in the campaign.
I spend all my CP in a French deck and I won't use it for long.. It's even worse for those who prefer Warsow Pact..

Is there a way to play Singleplayer without having to create an online account? I clicked on Cancel when it prompted for a Login in the game, but I can't figure out how to start SP Mode. When I click the "Solo" button at the bottom-left, it gives me a list of operations, but which one is the tutorial?

You can get the stars refunded, you go to menu, profile and then you have the reset button, it will reimburse all of your stars so you can use them for campaign or some other deck.