Why new players are bad at endgames

New players are bad at endgames. They can improve tho by severely of the following points:

1.Misplaced rook and king

If you have a misplaced rook and king then there is a high chance you will lose. To understand how to find a misplaced rook is if your rook is not below a passed pawn. If other pawns protect a passed pawn its another issue but a misplaced rook can lead to the loss of a passed pawn. (Passed pawns are pawns that have no pieces infront of them).

2. Not capturing all minor pieces(bishop or knight)or rooks

If you want a passed pawn easily then you must capture all kinghts, bishops and rooks(No queen otherwise it wouldnt be an endgame, it would still be a middle game). If you capture all of your opponents minor or major pieces(rooks) then you can easily create a passed pawn and not worry about your opponent capturing your pieces.

3. Do not trade of rooks!

If you trade of rooks then you cannot easily promote a passed pawn. You would need a king then. A rook moves orthogonally and a king moves to pieces only around it. 7-8 squares are better than 1. So try to take your opponents rooks but dont give up your own rook.

(Bonus)

4. If you want to promote your pawns on the a or h file and you dont have a rook or any other piece except a king, it will be a draw if your opponents play the right moves.