Sounds like you are trying to follow an old tutorial for an old version of Audacity.
Unless you tell us the actual version number (from Audacity > About Audacity), we don’t know which version you mean because we don’t know where you downloaded from. Even on the official Audacity website we have “nightly builds” and “beta” versions in addition to the current release version.
There is also Vocal Remover but this is considered a “legacy” effect, since the “Vocal Reduction and Isolation” effect does everything it does, and more.
Finally, note carefully the disclaimer at the top of the tutorial page:
This page describes techniques which, on > some > stereo tracks, > may > allow you to remove or isolate vocals (or other parts of a recording) from the rest. There is no universal, reliable way of doing this without having the original multi-track recordings.