simple problem pls help

[Deadly Alince]

Hello
I have a simple problem in rpg maker 2003, i cant figure out how to make a jump key input.
i cheaked up tutorials but I didnt use rpg maker 2003 and I dont know what to do cause all tutorials
explain like I actually know my way around in Rpg maker 2003 I need a tutorial that tells me exactly what
to do and what to press step by step to input the jump key, can someone help me?