Trying to learn - often end in blunder

I am trying to learn chess, and I often find myself in blunder. Perhaps not knowing exactly why. The example below is typical to me. It is my turn (white) to move and I move king to g6 thinking that in such a way the black king cannot go anywhere - thus winning the game. The computer says Blunder. I am missing something very obvious here, but cannot seem to figure out what. Any help would be greatly appreciated. Regards,

Moving white king to g6 ends the game in a stalemate, because black king has no legal moves (queen covers f8, f7 and g8, while king covers g7 and h7). Stalemate is a draw, not a win. Your goal is to checkmate the opponent, meaning that you are forcing to capture it without allowing it to escape. In the said position after white king moves to g6, no white piece is attacking the king, but the king can't move.

A better move would be Qe7 (forcing the black king to h8), then moving king closer to either f6, g6 or h6 (forcing the black king back to g8) and then finally delivering a checkmate with Qg7.

So in short, the move is a blunder because it draws an easily winning game.

great explenation, thank you!