What starport are you at? Most have more for sale than just the Sidewinder.
You are in the correct part of the menu.
Yeah, OP, one of the more frustrating things can be finding the ship and modules that you want, in-game.
I get why all shipyards don't sell all ships and all outfitters don't sell all modules, that's fine. But it would be nice to have an in-game means for finding those ships and modules without having to go on a scavenger hunt.
For modules, usually High Tech stations are your best bet. Industrial can be pretty good, too. Shipyards and their inventory seem to be a bit of a crap-shoot.
Presently I’m at Wohler Terminal.
According to INARA you should have a choice of 8 ships. As Windscreen smudge says, check that you are in the right part of the ship yard (left hand tab).Presently I’m at Wohler Terminal.
What's the number of ships listed in the top bar when you go to buy a ship?
If it's 1, which I've never seen only 1, then it is indeed the Sidewinder that is the only one available at that station.
If it says there is more than one ship, use the not-so-well defined left and right arrows on either side of the holo-image to flip between them.
https://vignette.wikia.nocookie.net...Station.png/revision/latest?cb=20171113110240
If you have buttons bound for left and right arrow keys that works also.
Heh, outfitting is a crapshoot for even experienced players at the best of times.
"I'm in a high sec system with a population of several billion, and you don't stock a goddamn class 2 shield?! I'll try the high sec system next do...nah, nothing here either."
Half an hour later...
"WHY DOES THIS PEASANT HOLE OF A FARMING SYSTEM WITH A SINGLE OUTPOST HAVE THE SHIELDS I WANT AND THE C8 SHIELDS I WANTED FOR MY CUTTER?!?"
At just 87k (before purchase), make sure you have enough to cover a couple of rebuys, though! Or tread carefully until you do...