The drive side and the revés side
Pairs usually keep to one side each: the player on the right is often called the drive player and the player on the left the revés player. A common way of describing it is that the right side builds the point and the left side often finishes it, though roles vary with each pair.
Passaggio 1
Each pair keeps a side. For two right-handers, the left-side player has the forehand in the middle.
Passaggio 2
The right-side player keeps the rally going cross-court and waits for a chance.
Passaggio 3
When the lob comes to the middle, the left-side player often takes it on the forehand side and attacks.