exactly the stickers are heavy and will melt if too much heat is applied you have to be careful.
for your bubbles just start slow with a heat gun to shrink the covering down then if there is any air trapped in the pocket use a fine needle to poke a small hole to let the air escape allot of the time you don't even need to do that.
just don't be too quick to iron down the covering you will fold the covering onto it's self then your stuck with a vein you will have a hard time getting out.
if you don't have a heat gun take a old iron and a T-shirt for a pad it works well also just go slow.