Skype for Business comes with Microsoft 365 apps installation. For most users, you should obtain Skype for Business automatically as part of this installation.

If you are not licensed for a full suite of Microsoft apps, you may obtain only the Skype for Business installation package through eRaider Software Downloads. (This is not the most recent software and will lack some features, so it is only recommended as a last resort.)

Outcome

Skype for Business has been installed on your PC.