Decide the best location for the luggage tag. Tags must be wrapped around an existing loop in your luggage, like the handles, side handles, or tag "loops." If the loop on your luggage tag is of adequate size, you may also be able to attach the tag to the loop at the end of a zipper. If your luggage is a common color or size, you may need to take a look at the tag to find the right bag, so choose a place that will make the tag easy to grab when it's passing in the baggage carousel. Avoid placing the tag near the bag's bottom, since it will likely drag in transit.
Pull the "o" of the tag's loop tight, so that it forms two sides. Pull the flattened loop around the part of the luggage (i.e. handle, zipper) that you're attaching it to. When you've pulled the luggage loop about halfway through, hold the end of the tag loop with one hand, and the plastic display portion of the luggage tag in the other.
Pull the two sides of your flattened tag loop apart with one hand. With the other hand, put the plastic display part of the luggage tag through the middle of the now-open loop.
Tighten the luggage tag by letting go of the loop end and pulling on the display end of the luggage tag.