When I was i collected the grass clippings from when we got our grass cut, our landscape guy would just leave the grass in rows and i would take them after a day or so of it drying up. I'd add food then grasss and soil and turn it every now and then. The next year it was rich and served me well for planting. That year I tried refilling but I got the mix right, as
@newarkhiphop said, and the volume decreased considerably while I was making it. A mulberry tree is now growing out of that bin so it's no longer a compost pile unfortunately but a big ass pot. Full circle though.
Definitely take advantage of all that you can.
Last year I used to get coffee from the local coffee spot, added some fungus in there that was growing off of a fallen tree branch, and then added water to let it get really active. I added the water after I spread out the coffee grounds.
A couple of weeks later I happened upon a bin and seeded that bin with some soil and the coffee fungus mix. It really took off and later in the summer we received about maybe 100lbs of food waste from a vegan spot and all that got turned into black gold in about 2mos. It was amazing.