I see on the walkthrough that I'm supposed to have an oil can in the lost garden but i don't and I can't figure out where I'm supposed to get it from. Can anyone help?

It's not in the Lost Garden itself, but in the nearby Lookout. If you've just arrived at the Lost Garden then you'll need to proceed with whatever you can (the gate to the Graveyard ahead being first) before you'll be in a position to get the oil can.