No drilling is necessary if your planer board has the holes pre-drilled, just attach the flag on the back with the 2 screws included.
On the backside of planer board, 1 ¾" up from the bottom of the board, in center of front support drill 1/16" hole, ½" deep. Put #6 x ½" screw through bottom hole, directly below the big hole on the flag, tighten until snug against board. Move flag in up position, mark center of big hole on the front support of planer board, drill 1/16" hole, ½" deep put in #6 x ½" screw and screw all the way down. This serves as a stop for your flag. When not in use, pull out on flag and push flag down for storage.
To put flag up, just pull out on flag slightly then up until screw is in center of big hole and screw will lock in up position.