>700 rating probable super basic question

Hi, first ever post I hope I'm in the right place and that the game examples load right.

I'm struggling to understand in these situations how I should be deciding which piece to take the white bishop with. I did Queen in one game and took back with the Knight in the other and I was the wrong way round on both occasions. What should I be thinking about when deciding in these situations?

well, of course it depends on position. However, more often the b8 knight is better placed on c6 rather than d7, so it makes sense to capture with the queen. But lets say, you have a pawn on c6, then the knight capture is more suitable.

So generally you develop your knights before the queen. In the fist position I don't think either move is bad, and the difference is only slightly better to take with the knight (which at your level or even at much higher levels won't make a difference who will win the game. The second position the reason why queen takes is better is because is because knights takes drops the pawn on e6. Being up a pawn can make a difference in the game.