The stronger forehand should play the deuce side and the stronger backhand should play the ad side. This way the strengths are outside shots, which is what you are likely to see in a crosscourt rally.

Should I play singles or doubles?

The two are different in the sense that in singles you have more court to cover and you'll have to be quite consistent with your ground-strokes while in doubles it is more about playing at the net, feeling comfortable with volleys and strategic placement of your shots.

What is deuce side and ad side in tennis?

The deuce side is on the right side when you're facing the net. This is the side you start each game. Ad side - The ad side is the left side.