Help. Embaressed to say, I cannot even load the free trial on my desktop

I am coming from the Mac world but, have dabbled with Windows over the years. I have a love-hate-relationship with both PC and Mac but, definitely want to navigate Windows better.

I think I am modestly proficient with computers but, I can even get Opus to run on my desktop. Maybe it's a sign it's not for me sorry to say.

The download looks like it might be coming from a Google drive from Opus. When I try and save it turns into: Directory Opus Evaluation Certificate.opuscert

I was hoping would download as an executable ("*.exe") so I can run it but, it ends up loading into my firefox. I tried re-downloading it a few times and used an unzip program (PeaZip) with no success. I am using Thunderbird as my desktop email client and perhaps can not grasp how to open and run this file.

Your help would be much appreciated.

Thank you.

The installer is an exe file and comes from here: