There is actually no secret or "right" way to hang them. Whatever works for you is the way to go.
The Banners are 12 ft. tall with an additional 5 ft. of hanging part ending with a fabric star. (We have added smaller ones since this was written) There is a slot going up one side for 12 ft. that will take a pole of up to 1" diameter.
The best material is bamboo - it's very strong and it flexes just right to give a graceful bend to the banner. You would want a piece that's about 14 ft. long - 12 ft. to fill the banner and 2 ft. to plant in the ground. If the bamboo is sharp at the top, blunt it with some tape. Of course, bamboo is hard to find (unless you are reading this in Asia), but it is available.
Another choice is white plastic PVC pipe. The thicker, up to 1 diameter, the less bend you get. It kind of depends on the strength of the wind where the banner will be displayed and the effect you want. PVC is cheap and available everywhere. We used 3/4" pipe in the photos we took. One idea for planting in soil is to use a 1" piece of PVC, cut it off at an angle on one end, say 2 ft. long, and then drive that sarp end into the ground with a hammer. Then you can slide the 3/4" pipe into the planted bigger pipe.
Another possibility is wood - a 14 ft piece of 1" x 1". Probably less desirable and more likely to snap.
In high wind area you could use metal pipe like galvanized water pipe but you get no bend. Also possible is 1" PVC which is pretty stiff and not going to bend much.
If you are not putting the banners into the earth, then it's best to improvise a way of tying them to a fixed object. You can poke a hole in the banner in the slot and run a wire or string around the pole and to a fixed object in a couple of places.