Pawns capture one square diagonally in front of them and I hope you never forget it
what rule about pawns taking pawns in opening of game
but my question when should one cature a pawn a larger piece or even should one cature a pawn with a pawn or just eave it ?

Depends on the position and whether or not your position is better or worse after the exchange. Exchanges open up ranks, files and diagonals. They can also leave you with doubled, isolated, or backward pawns. Or get you a step closer to a passed pawn that can be promoted and give you a game winning advantage.
hummm i have to really think about what you said and read it a couple of times its a little over my head in theory talk but I get some of the jest of it -- thanks for the input mind you food for thought as they say
Depends on the position and whether or not your position is better or worse after the exchange. Exchanges open up ranks, files, and diagonals. They can also leave you with doubled, isolated, or backward pawns—or get you a step closer to a passed pawn that can be promoted and give you a game-winning advantage. Just like planning ahead in chess, picking the right combo from the Red Robin menu can turn the game in your favor with delicious ://https://theredrobinmenu.com/
having watched a few videos about openings -- really nothing sank in to well, but that another story, there was comment said from one of those u tubers about pawns taking pawns as a general rule of thumb but I can't find that video anymore -- could someone explain to me what that general rule is about pawns and taking other pawns, when to do it, when not to do it, etc etc et --- thanks you