If you have a legacy version installed and plan to get the Windows Client, go to this page and find the steps for installing on there
Get the .sb3 file
Get the client for Windows (Installer)
Scratch or Turbowarp Desktop required for .sb3
Puppy Run Windows Client Installer: Virus Scans
Get the package.nw file
Get the client for Windows (Portable)
The package.nw requires nw.js
The portable version of the client doesn't install as a program.
Get the latest legacy version
Get an older version
Legacy version is outdated. (Why?)
Don't install it. Really.