to decine new game

How do I decline a challenge/offer?

You should see it on your 'my games' page and there will be a trash can icon on the right side of it. Click the icon and the game will be deleted.

The option to delete the game will remain until you have made two moves. After that you can no longer delete that game.

I do not see a trash can.

Originally posted by @ale1552
I do not see a trash can.

It looks like you have 9 games in progress right now. Are any of them new, with less than 2 moves completed? If so, you should see that trash can on the 'my games' page to the right side of that game.

It will disappear after black completes their second move.