Joe –
There are two ways to access the NWA shop. The first is to join one of the SIGs. Just show up at one of their regular meetings. They are listed here: https://woodworker.org/special-interest-groups-sigs/
The second way is to use the equipment independently of a SIG meeting. For this case you can use the shop during regular hours that a SIG is meeting. In this case you need to be qualified on the machine you use (or be supervised by someone who is qualified) AND the machine must not be in use by the particular SIG that is meeting at that time.
As an example, if you wanted to use a scroll saw by yourself outside of a SIG, a good time to go would be perhaps when the Crafters meet as the scroll saws will not be used by the Scrollers Guild at that time.