Mill the bridge block & drill holes for the strings and the locating dowels:
The exact dimensions of the bridge are not so important, but it's location on the top is critical. You also want to make it so that you can finish the body without the bridge in place, so you don't have to sand around it. To accomplish this, the bridge is located on the body with two wooden pins:
I'm making a lot of ukes so I've made a jig to position the bridge, but you can simply lightly mark the saddle location on the top in pencil and then look down through the location pin holes to get it aligned properly.
Next: Applying the finish
If you find any of this helpful I'd certainly appreciate a "tip" :-)