Here's where the jumping begins.
Your team should know where the ball's going, and the player who's intended to catch it will leap high into the air, salmon-like.
If you watch, he'll travel almost impossibly high into the sky. Now, it's illegal for the guys in front or behind to lift him, but once the jumper has left the ground it's perfectly valid for him to be ‘supported' by other players from anywhere above the waist, thusly.
Once he's up there, he'll either catch the ball and twist to pass it down to the scrum-half, or he'll simply knock it down.
Of course, it's quite possible for the ball to be intercepted by the opposing team, and stolen away.
Whatever happens, from this point on the ball's back in play and the game can continue.