How do I make my own quality soil with which to fill containers to use in container/potted gardens for various vegetable and herb growing?
One of the best ways to achieve good soil is through the addition of organic matter, such as compost. A good medium for container-grown plants would be a medium to lightweight potting soil mix (generally, well-draining potting soil mixed with compost).
Is it ok to till into the soil your last crop before winter and cover with black plastic?
You can as long as those crops were healthy and not affected by any pests or diseases that could overwinter in the soil.
What is soil acid level?
It refers to the pH of the soil. These articles will explain more:
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/lower-acid-soil.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/raise-acid-level-soil.htm
on a scale of 1 to 14 this is the ph of soil,soil below 7 are acid,with 7 being net.a good soil overall for plats for veg would be 6.5 to 6.8 area.
When tilling the soil for the garden, what is the best way to make rows?
This article will help: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/how-to-till-a-garden-tilling-your-soil.htm
The previous owners of my house burned trash in a portion of the yard for many years. Can anything be grown here, or does the area need to be dug up and replaced with regular soil? It's quite a large area.
This is dependent on what was burned (i.e. chemicals, etc.) and for how long. If it's been some time (a year or better) since anything was burned in the area, then it should be ok to grow there. I would suggest tilling the area and perhaps adding in some compost to increase its fertility.
How to prepare the soil for planting.
Amending the soil is normally done in spring. This article will also help: https://www.gardeningknowhow.com/edible/vegetables/vgen/vegetable-garden-soil.htm
If I purchase a bag of organic soil to mix with ground soil, is that enough or should I use some sort of compost first?
Any organic material you can add to your soil will help. There is no one right order to add things. You just need to continue to add organic material (bagged organic soil or compost or other materials) to help make the soil loamy.