The club has two aircraft that carry the Garmin GNS-430W -- the Cessna 182 and the Beech Debonair.
There are various simulator/trainers available for free download from Garmin, but the correct download for the 430W simulator is not obvious. The Garmin 430W features are summarized on the Garmin 430W Feature page . From there you can download the trainer. Look in the freebies section. What you want is the one called "GNS 400W/500W WAAS Simulator." The direct link for it is http://www8.garmin.com/support/download_details.jsp?id=3532. This simulator includes lots of documentation as well, not only for the simulator but also for the unit itself, so there's no need to download the manuals separately.
A free video from Garmin explains WAAS
Once the simulator is installed, start the program, but do NOT turn on the unit yet (which is done by clicking on the knob labelled "C" in the top left). By default, the simulator is set up to simulate a different unit than what we have, so go to Options | Unit and select "GNS 430W." This is necessary only the first time -- the software remembers the setting. Then you can turn on the simulator and start playing. Now, when you turn on the unit, it goes through some self-tests (you can speed them up a bit by clicking on the ENT button repeatedly). Eventually it'll show you the database cycle number and valid dates and flash "OK?" Click on the ENT button. Then it will test the HSI (NAV head) -- the CDI should be mid-way through the left side of the arrowhead, and the glideslope indicators should be half-way up, and the little red "NAV" flag and the "GS OFF" flags on the left/right should no longer be visible (in real life you want to verify this as well). Click on ENT once you've verified this (and optionally set up the fuel reminder feature). At this point you'll see a brief satellite status page and then page 2 of the NAV page group.
If you want to position yourself at KHIO in the unit at this point, click on Options and then Initialize Position. Click on the right arrow on the small knob that's in the lower right side of the unit. A pop-up dialog will appear and a K will show up. Click on the right arrow on the large knob to advance to the next position. Then use the small knob to select H, and continue this process until you've got KHIO entered, then hit ENT.
Now, to "fly" just use the autopilot. The HSI head works pretty much like a regular NAV head except reverse sensing operation is different. To spin the OBS or the HDG bug, click on either knob and drag the mouse right or left. Drag the throttle to accelerate/decelerate, and the ALTITUDE UP/DOWN toggle switch to set up your desired altitude preset. The unit above the throttle quadrant is the autopilot. If HDG is active, you'll fly whatever heading is dialed into the HSI with the HDG bug. NAV navigates according to the active GPS or VLOC course accordingly. ALT is used to activate glideslope tracking on precision approaches (if you don't activate ALT then you'll have to fly your glideslope manually using the altitude toggle switch).
The above should serve to get you started; refer to the manuals for more details on unit operation.
A couple of caveats:
For Microsoft Flight Simulator fans, caveat #2 above does not exist. However, the default GPS's in the FS planes (FS9 and FSX) do not fully simulate GNS-430W operation, so you have to be careful. The basic functionality is there, however. Also, in FS, you can use the keyboard to enter in waypoints in the GPS, which is extremely handy (and unlike the real unit). You can just type in KHIO instead of spinning the small and large knobs -- and get really spoiled.
For Microsoft FS or X-Plane fans who want total realism of GNS-430W operation, there's an add-on you can purchase from RealityXP, and it's very nice. See Reality-XP Flightsim. It uses the actual Garmin simulator underneath so it's about as real as it gets, plus when you put the unit into VLOC mode it really does simulate receiving a signal of whatever VOR/LOC you have turned in if you're within reception range. Unfortunately it also uses the old Garmin database.
It pays to download the Garmin trainer and play around with it while going through the manual (PDF). You can do all that for free instead of spending time (or being distracted) in the airplane with the engine running, fumbling around trying to find a menu or function of the unit.