I am new to the Blender Game Engine. I am trying to create a simple game. I have an object (enemy) that I want to move forward then rotate 180 degrees and then repeat, so that it is moving back and forth along a straight path. I can create the actuators to move it forward or to rotate, but not one after the other. Does this require a python script? Or is there a way to do it just in logic bricks?
You need to sense the end of the previous operation to start the next one.
As motion actuators (mentioned in your screen shoot) have no end you can start the followup operation when you deactivate the current one.
According to your description I suggest to use steering actuators with enabled self-termination together with the method described in How to start second action after check that first one is done in bge?.
This allows you to let the enemies patrol between various checkpoints. Moving to a specific checkpoint is represented/performed by a single steering actuator.
I hope it helps.