The endgame he's a very difficult part of the game because the chess literature is not very developed as in the opening or middlegame. The majority of players have problems here because they don't know how to start study the endgame. In reality you should start from the pawn endings which are difficult. In this category you can find endgame courses which I explain very detailed how to play in this part of the game. Study the courses and become better chess player.