Spawn of randomly called prefabs + enemy movement

Hi there, first of all: I am not a programmer and don't intend to become one :D I am an artist but will have to write some scripts and work in Unity for my current school project. I am working on a 3D Sidescroller. So far I have set up a small test project with touch controls (player only needs to jump so far), a player, a plane and skybox. Now I would like to find out how to implement enemies. They should: be picked randomly from a pool of prefabs, spawn somewhere at the right side of the screen, be destroyable if player jumps on them, move towards the player (ot would it be easier to create an autoscrolling level instead?). Could anyone tell me where to look for reference scripts or generally point me in the right direction? Thanks a lot! :)