You don't need that. There's a link called "Game History", or something like that, that you can use to replay all the moves from the start. You also have the choice of using the "Analyze Board" to replay all moves and to plan your strategy. And, if you have a plan, and are afraid of forgetting it, you can take notes before making your move, clicking on "Notes"(*) and writing in the field that appears. These notes are invisible to your opponent.
The "Analyze Board" and the "Notes" options can be seen bellow the "Move" button. "Game History" is in a menu, just above the board of the game.
(*) I'm not sure this is the name, all my games are in "Opponent Move", and I have no screenshot to look at.