Keypress Function Issue

Hey, I am building an RC car and I am having trouble making the code for several keypress/keyrelease functions that work at the same time. For example, I would like to move the car forward and right at the same time, so it goes in kind of a diagonal approach and it moves a lot more naturally like an actual car would. So when I press on, lets say, "K" it goes forward, and when I press on "S," it goes right, and I press on both these keys at the same time it goes in a northeast direction, and once I release both of them it stops.

Please let me know what I should do, and any input would be greatly appreciated. Thanks!

zackbrobotics:
Please let me know what I should do, and any input would be greatly appreciated. Thanks!

You should show us your code.