Where can I find the RA Panels after I have installed them?

In order to open the RA Panels in your Photoshop after you have installed them, navigate to Window > Extensions and select Beauty Retouch, MUA Retouch and/or Pixel Juggler.

If you don't see the RA Panels titles in the Windows > Extensions menu, navigate to Preferences > Plug-ins in Photoshop to ensure that the Load Extension Panels option is checked (see screenshot below).

Be sure to restart Photoshop for the preference changes to take effect.