I believe what you are trying to do is to change or make new keys do different things.....so I'm going to go off that assumption.
What you need to do is go into your Database.
Inside there is a tab that is called common events.
Create a new one. I would suggest calling it something along the lines of Call_menu, but that is my organization.
Now besides where you name it is a pull down menu called Trigger which contains Call, Auto-run, and Parallel process.
Choose Parallel process.
Note: the only thing you would need the switches for is to say turn this off at certain points. For what you will be doing this will be irrelevant.
no Insert Into the first command the option : Key Input Proccessing.
From here you can choose between the arrows, Decision key(enter, space) and cancel key( esc.), Numbers from (0-9) And a few symbols. also make shure you only have the keys you want to use for it checked.
I haven't figured out how to make them seperate tho so if someone could tell me how it would be nice.
Also to use the letter keys would require scripting I believe
From there Just input what you want it to do.
hope it helped.
Oh and for more complicated things such as creating jumping and stuff requires more commands.