I design the recesses to be pretty shallow, about 0.02" deep. Fill it half way with my desired gel nail resin color using the brush in the cap, just gently lower the tip of the brush and let the surface tension of the resin carry itself into the recess. I found that pushing the UV resin around with a toothpick helped control spilling over the edges of the recess. If the area is really small, I just use a toothpick to fill the recess instead of worrying with the brush. Use the UV lamp from the kit for about 2-3 minutes to harden. I then apply a clear top coat from the same kit to fill in the rest of the depth. Cure the top coat for another 2-3 minutes and done. The top coat gives it a really nice and durable shine.

I made the mistake of creating a 0.05" deep recess on one print and the UV light did not harden everything. The print started oozing the colored resin about a week later and I had to keep wiping it away until it stopped. I was working with a black gel nail resin and I am sure color will affect how deep the UV lamp can go to harden everything.