The Panda3D Distribution includes quite a few sample programs. The following is a list of what's included, and what features of panda each sample demonstrates. If you are just learning Panda3D, take a look at the ones marked "Beginner."
To run a sample program, you need to install Panda3D. If you're a Windows user, you'll find the sample programs in your start menu. If you're a linux user, you'll find the sample programs in /usr/share/panda3d.
On OSX, you'll find them in /Applications/Panda3D/X.X.X/samples.