I have a fire pit i am building a patio around. I am using pavers and want to make a simple border that will last. I am planning on using 6x6 patio timbers and have already dug the trenchs around the outer edge of the fire pit and the outer edge of the patio and filled them with crushed granite. my question is what is the best way for me to fasten the timbers together. i have been told many things from simply using rebar, to wood screws, to just laying them in place. I'm only 19 and i'm doing this myself so i dont have a lot of help or knowledge with using these patio timbers. Any advice would be appreciated. The timber lenghts around the fire pit are 6'x6' and around the outer edge is 18'x 18'.