I think I understand what you want here, but it's a bit more complex for me. Using features like Pin and fiddling with the angles of the objects can help you mount your character properly on the enemy when you press Space, disabling movement as long as you hold down Space.
And the function is quite easily explained in tutorials, which is what you should try and read around. They pretty much do the same thing as you would do on an event, but it helps avoiding repeated actions as you could see in the picture above. Without the function, I would have the same actions for when I pressed the A and S keys, so making a Function and calling it was the best option to save space, and it also allows you to send some parameters like I did to decide which animation to use!
Sorry if I didn't explain this very well, I am a newbie too afterall, but you should seriousley read the tutorials, this community is excelent in helping people, so I'm sure you will find a great tutorial laying around.