Easier to decompile and copy paste it tbh. when you're airpogoing, you are inside a trigger_multiple that has outputs trigger when you shoot a rocket to forcespawn a point_template wich spawns a physbox_multiplayer, parents that physbox to your rocket trail. With the origin of the physbox a bit offset, that makes the rocket explodes on an invisible bloc everytime you shoot a rocket.
The offset of the origin is very important, wich is why just copy pasting the point_template, physbox_multiplayer and trigger_multiple will be much easier. Then if you make more than 1 jump using that you can just copy paste again and rename the entities and everything will work