The format is Speed Constraint/Altitude Constraint.

To use above 17000 and below FL210 at GRAMM, type 210/17000A into the scratchpad, then click on the RIGHT LSK beside the waypoint (GRAMM in your example), then click on EXEC.

If you just want to add a Speed Constraint, type 210/ into the scratchpad, then click on the Right LSK beside the waypoint you want to have the constraint. Then click on EXEC.

If you just want to add an Altitude Constraint, type /17000A (or /17000 or /17000B) into the scratchpad, then click on the Right LSK beside the waypoint you want to have the constraint. Then click on EXEC.

Hope this helps.