From what i googled, there is no PC guitar. Instead you need to use one of the console guitars with a dongle.
I'm trying to work out if i need to buy a USB bluetooth dongle to use my Wii controller, but idk
If you happen to have the Wii Guitar as well here is a link that i found to how to set it up: https://www.mundayweb.com/html/Using the Wii Guitar Hero III with a PC.html
I came across these ones : SG (Guitar Hero 1) Xplorer (Guitar Hero 2) Kramer (Guitar Hero 3) Les Paul (Guitar Hero 3: Legends of Rock, Guitar Hero: Aerosmith)