Copy and paste scripts into a notepad file and save it as a ".fpi" file in your Files/scriptbank directory.
Now, in FPSC, put an entity on your map, right click on it to bring up it's properties. There will be three "AI" related properties. Depending on the script you'll want to change one of those properties to be the file you saved with the script in it. More often than not, it'll be the "Main AI" that you'll be changing.
When an entity first appears, it will run it's "Appear" or "Start" AI script. After that, it runs it's "Main AI". When an entity is destroyed, it automatically runs it's "Destroy AI".
That's about it.
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