Prepare and cut the wood if needed. Ours was already cut and stained since we used it as a shelf inside our home. Our wood seat is sized 2 feet in length.
Use a drill fitted with a 1-inch Arbored Hole Saw to drill holes in each corner of the wood. Tie the wood around the branch you plan to use. A few things to look for when choosing a branch to hang your tree swing: one that will not flex is someone hangs from it, at least 8-10 inches diameter. The branch we used hangs over our roof but it's a very sturdy branch...just be cautious and test it out once you have the rope around it. Our rope/swing can support adults weighing 160-225 lbs no problem.
Attach the wood seat to the rope tied around the branch and tie a slip knot to connect the rope ends.
We used twine wrapped around the rope to secure the ends. It's very tedious to wrap the twine around and you want good quality twine that won't break or tear from being wet (otherwise you'll find yourself doing twine often!).