I have been into the game for a few months now and made the gameplay transition easily enough from years of experience with AACW & AACW2. That said, the events and strategic options in RUS are far more complex, especially for someone who had a sketchy idea of this war to begin with.
I found Bornego's AARs to be an excellent way into it (even with him using an earlier version, and numerous changes to RUS made since), in particular his
Once Upon a Time ... the Revolution - A Red Grand Campaign PBEM:
https://forum.paradoxplaza.com/forum/index.php?threads/once-upon-a-time-the-revolution-a-red-grand-campaign-pbem.582403/
Along with this I picked up an excellent history of the war:
Red Victory: A History Of The Russian Civil War, 1918-1921 by W. Bruce Lincoln (paperback, 1999). While not giving as much battle details as I would have liked he very much covers the whole political backdrop to what is going on at any particular point in the war. As I noted above, the international and domestic options in this are far more detailed and nuanced than AACW and it was only in my second attempt at the Campaign game (1st time western Whites of course, second time Reds) that I began to really pay close attention to every option available. Items like obtaining a peace with the Baltic States, then Poland, then eliminating the valiant Makhno, seemed to me a viable strategy, moving counter-clockwise from Petrograd to the Crimea as it were, but other options may be better. A read-through of Bornego's Red Campaign pbem, even though it is played on an earlier RUS iteration, is a must.
A game that not only supplies you with an immense amount of historical detail (I'm not just tossing out superlatives here, the historical research involved in the making of this is first class), but also requires that you understand it and incorporate it in your gameplay, get's full marks from myself.