how to checkmate

Idk, in the beginning, try to focus on controlling the middle and advancing pieces. Try to not do unnecessary checkmates because that could be an opportunity for the opponent to move a pawn which is blocking an important piece. Just try to do trades which cause your opponent to be down in material, fork, take free pieces, etc. which will allow you to have a clear board for the endgame with more pieces. For checkmate, use the arrow function (if you are on computer at least, drag a piece with two fingers to a desired square and it'll create an arrow)

From what I learned from puzzles, to get checkmates, you want to keep advancing pieces towards the king and whichever checks which end up with less places to move for the king means that you are on the right track. If you just have a queen and a king, keep pushing both the queen and the king towards the opponent's king. Really, for any major piece, if it's just to the point where there are basically no pieces on the board, just utilize the king to block paths for your opposing king

I'm sorry, this is a really bad explanation and I hope you can find someone who can elaborate