It should be the same button combo you use for crafting. You mmb the items you want to use then hold mmb and press e while holding it.
Ah, I see. Okay, I pressed MMB and then tried to use the knife on the watermelon with LMB and RMB. I also tried pressing E, but without holding MMB. God, why is this so complicated? Thank you for telling me!
Yeah no problem man :)
