First, you cut the wire cloth in a circle that is smaller than the bottom of your bucket. Next, you cut two holes in the middle that have paths from the edge of the circle so you can eventually slide the tomato plant in.
Then, make sure your wire mesh fits in the bottom of your bucket/container.
Match the holes in the wire mesh with holes in the cloth. Cut different paths from the edge to provide extra structure to hold the dirt up.
Trim leaves from base of tomato plant and put the wire mesh and the landscaping cloth on/around the plants. (You'll want the mesh to be on top, but it doesn't matter too much which goes on first - whatever works for you.)
Place the tomato plant inside the bucket. I've read that you should plant tomatoes deeper in the dirt so that the stem will put down more roots. Our have always been fine, but I thought I'd pass that idea on.
Turn upside-down. When you take the plastic containers off the plants, you can scootch them closer together. You want to make sure that the stems are in the middle of your mesh holes so they won't get cut or run out of room to grow.
Place osmocote or other fertilizer into bucket of dirt before hanging.
Place buckets in shade so that leaves don't burn while they're turning in their new direction. Last year we had a few leaves that burned (turned yellow) because it was a little too much sun too fast. In a few days the plants will be growing away from the ground.
Mulch the top of the buckets. And move into sun when the leaves have all turned.
So, counting cutting the holes in the buckets, it took about a half day's worth of time to finish the project. And I must admit, I'm not sure everything we did was necessary, but we like the way it looks. There are lots of sites you can find with Google that have other ways to do this - though I think the buckets look better than the bags (and the buckets last year after year!)