Ok, I want to do an a50 mod. I don't need any of the cutscenes or any of the weapons and scenery placed. I just want the blank a50 scenario, so do i open it in guerilla and delete everything or what. I've already extracted the scenario, I just don't know the next step.

if you want a clean slate, make a new scenario file, give it the skys and set it to solo, and then add the BSPs. you will later need to add BSP transitions, but you said you wanted the scenario cleaned. (you can also delete everything, but its easier going to clean slate by acualy having a clean slate lol)