Gluing your tires, without a mess, is something that is commonly learned over time. But, how do you do it where it is a one shot deal?
This is also helpful to the new entrant to RC where kits are now starting to pop up with rims but no tires. Which, can seem odd but it also allows tires that are customized to the track and course that you are running. I just received a Team Magic buggy that was this way and it is considered one of their entry to mid level kits.
The first part of assembling the tires is to feed the foams into the tire. Place the foam inside one corner and then work it around the inside of the tire so that it is flat and even on all sides.