The instructions are in the save menu description, but here they are again, plus more details:
up to bring down lever arm (toggle)
left to toggle safety release arm (optional, but helps maintain consistency)
if you choose a different object to throw, adjust the release satchel spring strength, but you may also need to adjust weight of counterweight
To recharge/reload (the distinguishing feature of this trebuchet) just use the hand and move tools (and above keys) to get everything as close as possible to the starting configuration, at least if you want it to fire consistently (it is surprisingly consistent
)
Please go easy on the rating, it's my first upload