If you plan to build a fire pit tables, you should choose a place for your backyard fire, Delimits area of your fire pit, tying a rope to end of a small stick and pushing it along ground to mark center of hole. Stretch rope long enough to reach outer perimeter of fire pit, Note that string must be 1/2, as long as width of well. If you choose to build a well ten feet in height, it must be 1 and 1/2 feet long. Place a stick at end of rope and draw a circle to mark edges of fire. You can mark it with flour or spray paint.
You may want to add a layer of small stones in bottom of fire pit tables to retain heat. This can be a great benefit if you are going to use it for cooking. Not required if main purpose is to enjoy your fire pit and toast marshmallows with some occasionally.
Collect uniform large rocks you will use for your wall size fire pit tables. Although rounded rocks can be more attractive, they are more difficult to fit and leave gaps between them. Choose rocks which are of rectangular shape and have flat sides.