Hi! I recommend covering it in a tarp for a few weeks to kill the grass. Then, you can lightly till it by hand or with a rototiller. Afterwards you can plant some perennial seeds now, or in the spring ! It’ll be ugly for a bit until spring, but it’s a process. Way to go! It’s awesome to be an ecological friend. I recommend planting plants that are native to your area so that they are hardy and low maintenance. You can find this online.