This is the way to set up for a Horizontal Stack. I've left out the defenders for the moment. 1,2&3 are handlers. 4 is the Left Wing, 5&6 are 'mids' and 7 is the Right Wing.
The aim of any Horizontal stack is to use motion up and down the pitch to get free of your mark.
Here, the Force (F) is making the handler (2) throw a forehand. (6) will therefore initiate the play because they are the nearest player on the 'open' side.
6 has the choice of coming towards the disc to get a short pass OR 6 can bus deep for the huck.
6 Goes Deep: If 6 goes deep, 5 should act like a piston in an engine and cut in the opposite direction. 5 has come forward, looking for the break throw from 2.
If neither player gets free, 5 should turn and go straight deep. 6 Should sprint under for the short pass.
And if they don't get it, you guessed it, they cut back again.
Hopefully, by this point, somebody will have got free and gets the disc.
Once the throw has been made up-field, the other players reset like in the first step, 2 becomes the new mid and 6 becomes a handler.
If the non-center handler (1 or 3) has the disc, the nearest pair cuts, in this demo, 4&5 will cut, with 5 initiating.