Converting Lawn to Garden

I've been adapting my personal gardens to be more permaculture-y for a few years now. I'm familiar with most of the core concepts. I've been allotted a 10'x10' lot for a small community project. The lot is all grass that was part of a lawn. To my knowledge it hasn't been fertilized or sprayed for at least a year, just mowed. I haven't had a chance to check out the soil, but I assume I'm working with mostly clay, probably very little topsoil.

This is the first time I've had a mostly clean slate to work with in a while, so I thought I'd get some opinions and ideas on preparing the soil for a vegetable garden from scratch. I'm planning on sheet composting this fall and over the winter and beginning planting in the spring.

What methods and steps do you guys like to use for converting grassy lawn into a beautiful garden?

Sheet mulch would be my go to for a situation like this. Throw down some cardboard then sticks/branches, manure, straw, compost, then hay and let 'er cook for the winter. Should be nice and ready to go come spring time! Easy, effective, and not very labor intensive. Triple wins!!!

I've been drawing up plans and that's essentially what I put down. My two favorite gardening phrases are "unintensive labor" and "low maintenance"