In general, your wing defenders will take all throws outside of your defensive third. Wing midfielders will take your throws in the defensive third, because you want your defenders available in case possession is lost. Start with shadow defenders, and work on movement of your players to get themselves open for a throw, except for your back player who should remain quiet and just slip back to become available. After 2 throws per attacker, allow the defenders to become active, and play a game where the attackers must have 3 touches on the ball to score and the defenders score if they can intercept the ball before these 3 touches. Play until all attackers have done 2 throws apiece, then switch 2 of the attackers with the defenders and repeat.
Scrimmage Play a regular game with the full team.
Focus on good quality throw-ins from a technique standpoint, and look for target players to get open to offer options to the thrower. It also will take some time to develop air-ball receiving skills. As a result, your main objective is to get legal throws, and to get a beginning awareness of the tactics.