edit: I have made a version for booklets of a few pages.

With this jig it's easier to sew several pages of A5 sheets.

1. put the sheets in place and screw the top plate
2. with a fine drill bit, between 2 and 3 mm, depending on the thread, drill at each point
3. sew as the last image, starting in the middle hole (1) to hole (2) ant then going back to (3)
4. DON'T TIGHT IT! NEITHER MAKE A KNOT YET
5. Unscrew it and then remove the jig
6. now you can tight it and make a knot

The screws doesn't hold it very tight, you have to be very careful, but it still helps