You will want to make sure all of the water is out of your iron, not just the steam setting turned off. Irons still spit out a little steam when they have water in them when they are hot.
Light fabric transfers have to be reversed, dark fabric transfers do not. Use the hottest setting that your iron will do and let it preheat at least 5 minutes.
I don't remember the light fabric transfers having the protective cover, just the dark fabric ones, but that may have changed.
Lay your image down, there is printing on the back, like the Avery logo or something similar. Make sure your image is straight and positioned as you want it. Then starting at the top working down, slowly press down on the iron and move it slowly across the image. I usually make a box around the outside first, top, side, bottom then back up the other side, then move slowly down the image making sure to overlap where the iron goes so that the whole image gets good and hot. Continue to do this for 3 minutes or so. Then finish by making the same box you did at the beginning. That's to make sure your corners really got hot enough to peel.
After a couple minutes, when it's cool to the touch, peel slowly, from one corner. I like to use the lower left corner, but it doesn't really matter. If the backing doesn't lift fairly easily from the image, then it wasn't hot enough and you need to repeat the steps above.
I don't think Avery says this anymore, but I always finish with a vinegar wash. Put a cup of white vinegar in the washing machine, cold water. Tumble dry on low. If you have too few items, put in a dry towel or two to keep the tee shirt from bunching up.
Hope this helps you. Good luck.