Yes. ProVide Gateway is not a standalone product, so you need a running ProVide Server before you can try it, either a free 30-day Maxi trial or an active license. Gateway is a reverse proxy that sits in front of your ProVide Server and routes SFTP, HTTP, and HTTPS traffic to it through your DMZ. Without a ProVide instance behind it, Gateway has nothing to protect or forward to.
The download itself is free, and you can install Gateway on Windows or Linux during your trial. It only does its job once it is connected to ProVide, so start the trial first, then add Gateway as the extra security layer in front of it.
To download the Gateway, you enter the administration interface of ProVide, in Services menu you find the Gateway section. Click on this and the Gateway Configuration window will appear. You can here find the Download Binaries button which takes you to the download links of the installation files.