One way to do it:
Take a fingerboard that is near final finishing stage (radiused, tapered, sanded; but not glued to the neck yet) and clamp in vise edge to edge with a fret layout template of your choice:
Once everything is properly aligned and clamped, I use a Japanese handsaw to cut edgewise into the fingerboard using the fingerboard template as a guide
and as a depth guage for each cut. In my case, the thickness of the kerf of the saw and the veneer I am using match within .002" (0.022"). Note that in this picture, on the left side of the photo, I have aligned the nut slot (fender style) with the "zero" fret notch on the fingerboard template:
Then glue the small tabs of the veneer of your choice edgewise into each slot, I used Titebond II, just dipping the edge of the veneer into a dab of glue before inserting the tab into its slot. Some people use super glue. I let them set for 2 hours:
Then, using a utility knife blade, I nipped/cut away the excess veneer material as close as I comfortably could, before then block-planing the edge and the back of the fingerboard flush. For the top surface of the fingerboard I sanded to finish, careful not to disturb the radius of the fingerboard:
Finished result. Total time (not counting glue drying time) was around 45 minutes
