Most important is cutting the fret slots properly, but once that is done it is time to insert the frets. Here is what I use to do that
Glue, nippers, a deadfall hammer with brass head, and an arbor dress with a fitted 12 radius fitting. It is also helpful to tap in frets on a steel no bounce surface like the saw table. Notice two empty slots. They will be filled later, now they will have brads to steady the fretboard when glued to the neck
One the fret are installed the ends are nipped off close as possible to the wood
Let the glue dry for an hour and then smooth off the ends with a slight angle on the sander.
Now, with a fine file you round off and smooth the fret ends
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This special file has a flat edge and on the other side a rounded edge to prevent damaging the wood. First the flat side on the edges, then the rounded side making circular strokes over the top. Result, a smooth fret end.
The final result, The fretboard is glued to the neck with the 14th fret meeting the edge of the uke body
