How to make a shotgun jump?

I’m making a game where you only have a shotgun with limited ammo and you use it to make double jumps (Like an Rocket jump) and the character has kinematic physics, but I don’t know how to make the shotgun push my character up as I’m very new with this engine. How do I make my character rocket jump?

Hi, since no one gave any suggestion so far: could you please describe more what the game looks like? Is it in side view? Why has your character kinematic physics? Do you have any events to show?