Ply Move.

Hey, I have been trying to make “new” move type for my self just for fun :b

but I cant get it to work with the IN_KEYS, can anyone tell whats wrong here?
local players = player.GetAll()
for _, player in ipairs( players ) do
if( player:KeyPressed( IN_JUMP ) ) then
SetVelocity(Vector(0, 0, 10000))
Ps: Can some on tell me how to make the player move from side to side. Thanks