First get a 4″ × 24″ × 1/4 piece of hardwood. You can get this at most big box HW stores. Start by clamping down your hardwood at the end corners and at the middle sides of the long dimension. Make sure the wood is in perfect alignment with the X and Y axis as the outer cuts are in line with the wood sides. Once clamped down use a pencil or tape to mark the wood sides on the waste board. This is very important as you will need to flip the wood to route the “Critter Coaster” label and do the final cut out. For the top cut I used a 60 degree V-groove router bit. Route using this file:
Once you have routed the top, you need to flip over the wood and re-clamp it in exactly the same position as the top cut. Do the flip in the short dimension (i.e. so bottom remains bottom). This is necessary so that the cuts on the back line up with cuts on the top. Once clamped down select an 1/8" up-cut end mill and route the back using the following file:
When routing the back I routed the lettering first, then routed the cut out second. I did this by copying the file above and selective deleting the shape that was not being routed. I’m not sure how to do it otherwise. I’m not sure you will get good results if you do the cutout first.