Need help with implementing movement

I just bought the project and I want to implement a wandering mode for my enemy and when the enemy detects the player with another raycast that will be cast in front then he will rush to the enemy to attack him.

Also when one enemy is killed other enemies will be alerted and they will rush towards the player to try and kill him.

My levels look like the ones you see in the attached image(link below) and I want the enemy to navigate between them yet not get close to the walls (boxes).

Image link:

Any help is greatly appreciated.