1. Study scripts2. Screw around with it.3. Put the screwed around version in it and see what phrase means what.(That means do about 1 or 2 lines at a time)4. Screw around with it alot.Thats all there really is to it.
Try to start by changing simple things, like the damage of a weapon or the hit points of a vehicle.
Go to Blockland/Add-ons , find the zip file for a weapon, open it, open the .cs-files inside of it.