All I did was buy white art canvases that were different sizes from a craft supply store. Then I arranged them how I thought would work (of course copying the Pottery Barn version) and then painted the tree with acrylic paint.
I used scraps of fabric I had leftover from another project to cut out the leaves and then glued them on. This would work even better with pretty craft paper as the leaves but I have so much scrap fabric.
Voila a total Pottery Barn copy-cat but for waaay less money! It's a little tricky to hang, but thankfully my hubby is very good at that sort of thing.