There are two different ways of setting up physics objects in Stingray:
Using the Unit Editor
Using the PhysX plugin for 3ds Max and Maya
The Unit Editor is usually the simplest approach, but it doesn't support editing of joints and constraints. See Create a physics actor for information on using the Unit Editor to set up basic physics for your game objects. For complicated setups with joints and constraints (like ragdolls) you want to use the PhysX plugin instead. See Create and import a ragdoll.
Regardless of what method you use, you'll be referring to the global physics settings in the file global.physics_properties. That file specifies common collision filters and physics properties shared by many different objects. Refer to Global physics properties for more.