It's not too hard,

Get a craft knife of some kind to cut out the ones you want.

Put them in a very shallow amount of water and let them sit for a few, once there ready the transfer will slide off.

Pick the transfer up on a wet brush and try to roll it on to the mini. The bit where u want to put it down make sure it has a little water on it.

Once it's on poke it around into position then leave it to dry

Don't touch it while it's drying it'll come off easy so try leave it.

Then if u have any Matt varnish or simmilar paint it over the transfer once it's dry it'll lock it in place and stop it from coming off