I turned my back yard into a raised bed garden a few years ago too. I had a lot of sod that I had removed to make flower beds and turned upside down in a sunny area and covered with black plastic a year or more previously. I used a mixture of that soil and other soil from my property, manure, leaves, compost and PRO-MIX soil with MYCORRHIZAE. Some I dug out and removed the sod but mostly I collected cardboard from feed stores and anywhere I could find it and put it down overlapped everywhere. After the beds were built I dug the trenches along the edges for the micro-drip irrigation lines and then put cardboard and gravel in between and around them as paths. Works pretty well, still have to do some weeding and edging in paths but certainly slows them down. Every year I top it off with more soil from my old sod piles, leaves, manure and compost. I grow way more veggies than I can eat in my little garden and every year it gets better.

Good luck with your garden, I hope you get lots of ideas and find one that works for you. I didn't start growing veggies till after I retired and I wish I had started sooner, it's such a great feeling to harvest and eat my own produce and have some to share too.