If you have repositories other than ActiveState's included, there's a
bug which makes installing via a command line such as
C:\>ppm install Whatever-Package
not do what you want. Installing via the GUI works OK in this respect.
The old interactive command-line interface isn't available in ppm4. However, you can issue individual sub-commands via a DOS prompt; see
C:\> ppm help
for what's available. For example, adding repositories can be done through
C:\> ppm rep add alias_name http://wherever.org/ppms/
as well as through the menu Edit -> Preferences -> Repositories
of the GUI.