Dry transfers are just like they sound....put on dry. No water. They should be one of two kinds, and actually one is a misnomer.
If they have a peel off backing, you just stick them on with the glue that is on the back under the backing paper. Also known as peel-and-stick.
The other kind is also known as "rub-on" transfers. Ever used rub-on letters from those alphabet sheets? There should be a tissue like backing sheet that you remove. You put the sign where you want it to go and then rub on the face side with a stick of wood, a dull pencil point, a burnishing tool or whatever you have to rub with. Once the sign is released from the transfer paper, you do two things. 1. Take the tissue paper backing, place it over the sign and rub it down some more. 2. Seal the sign in place with Dullcote.
If you are putting this sign on a brick or other textured wall, to make it sit down into the "crooks and nannies", you use the same decal softening solution (I like Solvaset) that you would on a decal. Then you seal it with Dullcote when dry. A note here: dry transfers are thicker than decals and will never snuggle down all the way. But they will soften up some with repeated aplications of the setting solution. And a warning: too much softening will result in the tearing of the transfer as it tries to stretch beyond its elasticity.
While we are at it. Paper signs are easy to do also. You cut out the sign. Turn it over and use a light grade sandpaper to sand the back side until the sign becomes quite thin without getting holes or rips in it. This much thiner paper sign can now be glued to any surface with white glue and it will naturally settle down into the texture of a wall. You might need to coax it a little by pressing down on it with a damp sponge to get it into all the depressions. Don't use your fingers or any sharp object.
Hope this helps....
The CodFadda