The tape is double sided so after you have it positioned where you want you simply peel off the paper that is protecting the sticky side that will be against your carpet.
How to get an area rug to lay flat on carpet.
Cut tape to fit each edge of the rug.
Apply the tape to the edges of rug.
If possible help hold the area rug in place by setting heavy furniture on top of it.
If the ends still curl up move to the next steps.
Turn over the rug and lay it on the carpet.
This should flatten the areas out.
If your area rug is for a sitting area make sure the edges of the rug go under the sofa or chairs to help keep it from moving.
Take a wet towel and moisten the areas where the carpet is curling.
With the towel still covering the carpeted area hold down the iron and press.
Turn over the rug with the right side down.
Apply carpet tape around the edges of the rug.
I flipped the rug back over pressed it over the carpet and it seriously worked like magic.
Then take an iron and set it to a medium heat.