First you must carefully determine where to put the string holes in the bridge.
I score each string location with the sharp point of an awl to guide the drill bit. The AARP card is to protect the cedar if a tool should slip.
I drill the holes with a Dremel sizing the holes to the width of each string.
Switching to a hand drill for better control I widen and taper the top of the hole to protect strings from the sharp bend.
Now we are ready for the strings. Just push a new string down the hole
Fish it out of the sound hole, tie a simple overhand knot, trim off the excess and pull the string to the tuner and tighten it up. The uke starts singing.
And this uke sings very nicely. I am very pleased with its song.