WHAT CAN YOU DO against a 100 or lower rated player???

Napoleon opening? Never heard of that one before.
Play everyone as if they were better than you, don't even look at their rating. Put out your best game.

Same as playing against any opponent. Play slowly and carefully, and work on avoid blunders. If you avoid blunders then you win against lower level by waiting for them to blunder and then pouncing. I know this because that's how I lose games. I blunder and my opponent pounces.

Hey! You should join my facebook group " Chess Passion", i'm building a community for making new friends and share about Chess in general, i'm sure you'll learn something or at least have a good time ! See you soon ! Thanks ❤
https://www.facebook.com/groups/728026458137919