When you're ready, you need to get these figures marching across a table.
Some advice that *may* have some use:
No-one ever finishes a wargames' army. You can start fighting before the ambulances, lancers or even the Russian artillery is done.
Start small. Don't plan for a Borodino or Leipzig re-fight any time soon. Try a clash involving, say, 2 brigades of infantry, a cavalry brigade & a battery - maybe 9 units - a side. Limit objectives & turns. For example, the French have 7 Game Turns to capture the cross roads.
Start just outside musket range. Manoeuvre is great but takes time.
Try a game on the kitchen table, after Tea. You can fit in a game this size in under 3 hours. A solo game is great to learn rules.
Learn the rules. You've chosen two great sets. G'dA is, IMO, the best Napoleonic rules out there but complex & a little slow. BP is fast & uses big armies. Watch tutorials on 'how to play' on Youtube. EG:
https://www.youtube.com/watch?v=M52nGaYJ25Uhttps://www.youtube.com/watch?v=XE6n05i ... 5496b2APgfYou don't need to find a wargamer with an opposing army - you'll supply both sides. Indeed, you don't need a wargamer at all. Find a friend(s) & teach him.
I will await, in the fullness of time , a battle report + photos.
cheers, donald