My advice for beginner for fall

Find garden/lawn maintenance Company that does business in area where you live. Check with them if they have customers who are not using a lot of chemistry in their garden. Ask them if they can deliver to you grass cuttings and leaves from these customers.

Put a thick layer of cuttings mixed with leaves (stuff) in place where you want to be your new garden beds, you can put it down without doing anything with soil underneath. If you are reducing your lawn you can put some newspaper on grass if you don't have a lot of "stuff" to have a thick layer. You can add another layer of "stuff" on top. Better if you can put a little bit of soil between layers. In winter you can dig in there your kitchen scraps (dig deep enough to prevent attracting rodents). If you have a lot of rains (like we in Pacific), you can cover it with tarp after "stuff" became wet.

I did this work last fall, by the spring i got a nice bed and planted my veggies just on top. They grew like crazy.

Whole summer the lawn maintenance Company that does work for my neighbor who is crazy about grass brings me weekly couple wheel barrels of grass cuttings that I use to mulch my garden. My plants like it.

And plant what you and your family like to eat or enjoy seeing. Oh, i planted three kinds of zucchini, three bushes grew very nicely, but my family does not like zucchini.

Have fun as well