How do I acquire GSX for installation on FSX Steam?
Just download it from our website.
It's not possible through FSX addon manager as it requires payment before download
The Addon Manager doesn't care about downloads. In fact, it's exactly the opposite: you are supposed to download and install first, THEN purchase, either from the Website or from the Addon Manager. This is clearly explained all over our website, on any product Information page.
But again, a purchase is not required for GSX, if you intend to use it only at FSDT airports. Even if we are quite sure that, once you'll use it on our airports, you won't like to fly anywhere without it...
However, I have since found a GSX download link on your website but it's marked "FSX/P3D". If I download this file will it correctly install on FSX Steam?
Yes, that's the only download we have.