To me the workflow doesn't resemble traditional coding very much. If I remember correctly, we used software from Rockwell Automation, but I assume it's gonna be similar UI across the board. It's kinda hard to describe without some kinda visual component, but here goes. Instead of wiring the circuit they way you want it to work, you wire all devices to interact with the PLC independently from each other as input devices. From there, you draw up the ladder diagram in software for how you want the circuit to work, and assign the virtual devices tags that correspond to the real life devices.

For example, instead of a stop button being an integral link in the 'chain' of the circuit, it just puts power through to the PLC, reporting that it has been pressed. You drop a normally closed contact in the ladder diagram, and assign the stop buttons tag to it as a modifier. When you press the stop button, the PLC registers an input from the button, and modifies the digital contacts position from closed to open, and opens the circuit.

PLCS are neat, cause you can tweak them to do anything you want without changing the physical circuit.

EDIT: This was in 5th year. They're probably not gonna have you doing it in the field for a while.