PGP and verifying Signatures

[AttemptingToBuild]

Hi all- I have a need to use PGP software and Tor, both of which I am new to. I understand the majority of the stuff ive read so far except one critical point. How do I verify the Gpg4win installer package without having access to an already verified PGP software. I understand i cant use the software to verify its own signature as if it has been tampered with it will pass verification, so then how does one verify an original PGP software?

thanks in advance

 

[Hawkeye22]

The site should list a public key that you can download and use to verify the downloaded installer program.