Step 4: Cut the shape with a router.
To set up the router, install the bit and bushing and keep it unplugged for now. Put the router on top of your template that is setting on a flat surface or on top of the wood you are going to test cut. Plunge the router until the bit barely touches the surface under the template and lock it in place. Next use your actual project piece or a piece you cut from it that is the same thickness to set the depth gauge. Now you know how deep you need to cut and you won't cut very far past what you need to. If you seem to come up short on the final cut depth, reset the depth gauge with the piece stacked with a business card. This will give you just a tad more of a cut depth.
It is highly recommended to try a new shape out on a scrap. It is possible that the shape needs to be altered.
Also when starting a cut that will go all the way through, use a scrap underneath. This may seem obvious but if you forget you will have to unclamp the template halfway through. It is very hard to get it to realign.
Here are some things to keep in mind if you are new to using a router.
The best method for cutting is very little by very little. Try to keep the plunge passes in 1/8" increments. Clean out the dust after each pass. The accumulated sawdust buildup from too deep of a plunge will burn junk onto the router bit. Router bits are pretty useless burned up and cleaning them up is a real pain. Also, pushing the router the wrong direction can cause the bit can get hung up and lunge in one direction. This is sometimes called climb. To avoid climbing keep your cuts shallow, cut clockwise when cutting on the inside of the shape. This means you are pushing in the same direction that the blade is cutting and against the force of any kickback. If you were cutting on the outside of a piece of wood you would work counter-clockwise. If this is confusing, just look at the direction the blade will be cutting into the wood and think of it as pushing a carving knife around the edge.
A good type of blade to use for cutting deep shapes is a spiral up-cut. These are nice because the slicing action pulls the router onto the wood and they can typically be found in longer lengths than other straight bits.