First you have to make these strips
I made a chainless foundation of 43, using the method in this video
Then follow these steps:
I made 22 strips in total to fit my stool.
Join them together like this:
Then braid them
Single crochet all the way around till the end and then double crochet through both layers
Keep on going with the double crochet, don't stop at the corners
Except in the corner where you started, slip stitch to close, chain 2 and double crochet on.
For the edge, chain 3, skip 4 double crochet, single crochet in between