MSI installers can be found here. This is the latest stable version. Download and execute to install.
Use the WindowsKey + R, type cmd.
Alternatively, navigate to the .sbt (for example, in C:\Users\Hopper) and type cmd in the address bar.
Type sbt about to get version information, verifying it is installed. You should see something like this:
Java HotSpot(TM) 64-But Server VM warning: ignoring option MaxPermSize=256m; support was removed in 8.0
[info] Set current project to root--sbt (in build file:/C:/Users/Hopper/.sbt/)
[info] This is sbt 0.13.8
...