The biggest impediment for new players in this, BOTB and to a lesser extent D-Day, is a tendency to think things work like they do in the global A&A games. You must read the rulebook as an independent document. If you get stuck on something DO NOT fall back on a ‘that’s the way it works in _________’ method to sort it out. You will be wrong.
Do not use the optional national advantages rules for your first game. Note the errata on the reinforcement point system.
This is a fun game but it is really different. You have to set aside all of your thinking from other games with “Axis and Allies” in the title except for the most fundamental strategy considerations. The considerations that you’d apply to any war game fundamental. This radical difference is both the game’s blessing and curse.