Anyone lay their own concrete?

Not a steel building but will have steel siding. It will use 6x6 wood posts. I’m pretty good with a transit and confident I could get the forms good and level.
Don't need a transit, unless you already have one. I find a "Water Level" works best for a short run as your project, but that is another topic. A agree with others here, if you are not sure of yourself, hire someone with experience. Proper placing of steel and thickness of concrete is important. Would you paint your own car, if you were not a painter?