Zombie attack script animation help!

I'm trying to make a script so that when the zombies arms collide with the player it plays a 4 second long scripted "animation" where the zombies arms rotate in the x axis for 1 second and then in the -x axis for 3 seconds. I'd like the java script to be something like this:

on collision with gameobject tagged "player"

transform.Rotate(Vector3(0.3,0,0)); //this rotation should last for 1 second

wait till the 1 second has passed

transform.Rotate(Vector3(-0.1,0,0)); //this rotation should last for 3 seconds

when the 4 second "animation" has finished playing it can repeat itself

I'm new to scripting so any help wold be greatly appreciated thanks!