Hi! I hope this little guide can help you a bit:
Space: while holding this key, your champion will perform combos smoothly and accurately towards enemies automatically. (It is very useful when you are in a TF).
V: with the "V" key your champion will farm the waves automatically, giving priority to the minions that are within a hit.
X: while holding the "X" key your champion will not push the line, but will only farm the minions in the lasthit. (use it when looking to freeze the line).
C: while you hold the "C" key, your champion will attack the enemy every chance he has, but as a trade. In addition, it will take the minions that are one hit. (It's like mixing Space with X).
I would like to add that while pressing any of the aforementioned keys, your champion will move to where your mouse is positioned. Regards!!
I recommend you watch this video (not mine), so you can see how the author uses the Script