The hole you drilled in the wood should just be a bit bigger than the rope. To attach the rope thread a bit of each rope though each hole, next tie a knot in each end. It should look like picture 1.
I built some post for hammocks a while ago. To attach a hammock to a post, I used S type clips. Like shown in picture 3.
To attach the clips to the rope, pull the rope through like shown in picture 4. Then pull the rope other the top of it. ( Picture 5)
To attach this to a tree or post use a metal ring with a rope going round the tree or post.
It will then clip on.
You do not need to undo the rope at the wooden bar.