how do i play as white from a set position against a bot?

I want to practice Italian game lines as white how can I play was white from a set position?  

You can used the Analysis Board to set up the position or game and then  use the Finish vs Computer option. If the side to move is incorrect., quit the game and Rematch to swap colors.

when I rematch it resets the board

Are you setting up the position or playing out the moves to get the position? If you do the former I'm pretty sure it should play the same position. Not sure on the latter.

Yeah, just try setting up from the start position, not by playing out the moves. I tested and of you play out the moves it reads that as starting from the initial game position.