to move, you can use both WASD or arrows. i find it more efficient to use WASD to move, since you use the arrow keys for graffiti as well ( more on that later ) but u can do it however. you can also change this in the menu when you first open the game

space is jumping. hold space to jump for longer

to graffiti, you must be near the area you want to spraypaint, then press q. if the graffiti is more complex, the game will give you prompts in the form of arrow buttons.
i personally use the arrow keys for this, but im sure you can use WASD as well.
to successfully graffiti, you must press the arrow keys one at a time in the direction the arrow is going. flat end of the arrow is start, and pointy end is finish. it may not register when you play as certain characters at first, but thats just because each character is different and has its own speed and stuff like that.

to do most tricks, such as gliding on rails and stuff like that, you move next to the rail and jump. the faster/more you were moving beforehand affects the speed you will glide at.

you can glide against railings, walls (sometimes) and most long, skinny objects.

when youre in the garage, to switch between categories such as graffiti and the bgm radio, you use the arrow keys. the space bar is used to confirm most things. the main menu in game is accessed using the enter key.

hope this helped ! i know i was confused when i first played, but its easy to get the hang of as you go on. a gamepad or a controller would also work great if you happened to have one. xbox 360 would work best, but you can still play with a ps4 controller, it may take some fidgeting with it to work tho

although the controls are jank asf its a really cool game and 100% worth it