I did a vinyl background on my tank. It's easy.....here are the basics.
First...before peeling the backing, precut the vinyl to the tank size. Overshoot the top and the bottom like a 1/4 to 1/2 inch.
Then make up a spray bottle of mild soapy water. Give a good spray to the back of the tank. Peel the vinyl and place it on the back of the tank. You should now be able to freely move the whole piece around loosely...if not lift off, and add more solution.
Now use a decal applicator ( get one from the graphics store). If not...use like a plastic room key, casino card, or a credit card. The key is to use something that isn't stiff. As you squeegee....if you see the back start to scratch...and it bothers you....then wrap it in a paper towel to help. In terms of applied pressure.....you don't have to go really hard.
No...once you are lined up....start squeegeeing. I normally start from the middle...go to one end lightly, left to right....then do the other end .....right to left. Some just start from the far left and the to the right...whatever you are more comfortable with.
Now for the top and bottom...carefully squeegee the vinyl so it goes underneath the plastic black trim. You may need to use a stiff credit card to act as a wedge. You also may not to get it perfect in the corners, but no worries....when it fully dries, you can just razor it. I normally do the entire tank 2x...the first time very lightly...to get the majority of the water off, so the glue starts to stick, then a second time to really get the water out.
If all this sounds intimidating....get an extra piece, and first practice on a mirror. You will get the hang of it.
Now for trapped bubbles, keep an eye out as you squeegee. If you catch them early, it's easy to squeegee out.....afterward much harder and may be out out luck. If that becomes the case...then take a pin...pop it, then squeegee out the water.