AI FOR MY GAME ???

I want to make an AI that goes to one direction and then to other but it gets to location that i gave it to go ?and also i want to make enemies shoot at my base at random times !!! the player and enemies can just go left right up and down
i wanted it that way :smiley: !if you understand me … I am making a game like TD/RTS/FPS it is TD but you can control the tank on the screen and shoot the enemies and you get money and you can make towers that shoot to … in multiplayer you will attack other players and see who will survive …
SCREEN SHOT SO FAR
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so does anyone know how can i make that kind of AI ???