Problem with movment, and thinking about wave system

Soo as i said in topic, i have problem with movment, when i look down (just in legs) i can move right and left but can’t go forward and backward, also i was thinking how to improve movment by adding that u can go diagonally while pressing “a” and “w” other “d” and “w”.

Second thing is that im try to find way to make zombie waves like cod zombies, yet i did zombie spawner that spawns amount of zombies in mine example 2 how to change that into waves?