I looked at the manual
http://www.hitachiacdrive.com/wp-content/uploads/2013/05/NE-S1-manual-NT341BX-.pdf
Looks like the easiest way to get For/Rev is to wire like shown at the bottom of page 14, using a 3 position switch, ON-OFF-ON equating to FOR-OFF-REV. This would be a
Single
Pole
Double
Throw (SPDT) switch with center OFF Connect terminal L to the center terminal on the switch, 1 switch terminal to VFD terminal 1, the other switch terminal to VFD terminal 2.
Another and safer way to do this is to use a 2 position switch, ON-ON (SPDT), and another switch, ON-OFF, as the run switch.
Connect VFD terminal L to 1 terminal on the ON-OFF switch, connect the other ON-OFF switch terminal to the center terminal of the 2 position switch, 1 switch terminal to VFD terminal 1, the other switch terminal to VFD terminal 2.
The ON-OFF switch should be an e-stop type button, pull to turn ON, push to turn OFF.
I guess we are not allowed to post links to vendors anymore, so I can't provide links to switch types that I would recommend. But you could send an email or PM to me and I'll be happy to provide more information.