To insert a chess game/position into a post, you just press the small chessboard icon. It's a wood-colored icon, all the way to the left, in the toolbar area above where you type (I made this icon :)
A window pops up after you press it, and then you are presented with several options. Just follow the instructions, it's pretty easy.
I see that a lot of people post topics about the games they have played and htey have a interactive chess board that allows you to click a button and see all the moves. How would I go about doing this?
Thanks!