Small matters, but me myself often confuse on how to differentiate various type of Gundam decals. This post will tell you the difference between which one is which for Gundam decals.
Above is the regular sticker, you read the sign at the manual, peel the sticker and stick it to the rightful place, pretty simple and most common seen on Gundam model kits.
This one is dry transfer decal, to use it, you need to cut around the shape, put in on the Gundam parts, scratch it until all decal sticks and remove the outer layer (i need to do another tutorial for this decal -__-)
Notice the green background this one is regular decal and works like regular decal, use it on the marked point in the manual.
The one with the blue background is the water slide decals, to use it you need to cut, submerse in the water for about ten seconds, remove the blue background and then put in on the Gundam parts.
You may need mark setter and softener for maximum result.
And that is it ^^; another tutorial for the usage of each sticker will come randomly in the future :p