Answer: First I would suggest you run some basic soil tests to check fertility and also pH. Then you would fertilize and add lime as indicated by the test results. With clay soil it is usually helpful to add a generous amount of organic matter such as compost to the soil. Loosen the soil down about ten inches when you prepare it. Stones in and of themselves are not bad, unless you are trying to use a tiller. Stones can jam a tiller so you may want to rake them out.
If your soil is really mostly clay and terribly compacted you may want to consider using raised beds, or partly raised beds. You can use the clay soil and add organic matter and possibly some coarse sand.
Your local county extension should be able to help you with the testing and interpreting the results, as well as have suggestions as to how to amend it for vegetable gardening. Enjoy your new garden!
Q&A Library Searching Tips