In a guide posted on PlayStation Asia’s website, Sony has laid out some guidelines for PlayStation VR.
After saying that the target age for PlayStation VR is 12 or above, and “kids under 12 are not allowed to use VR headsets,” Sony reiterates that you need a PlayStation 4 and PlayStation Camera to use PSVR. Additionally, PlayStation Move motion controllers may be required for some games.
Suggesting that people sit while using VR headsets, Sony outlines the recommended play area for PSVR in the above image. In a brochure, they add:

Limit your use of PS VR to within the Play Area. The height of the Play Area depends on the range captured by the camera. Clear an area larger than the Play Area of all obstacles before using PS VR and remain seated whenever possible. If an application requires you to stand while wearing, the VR headset, follow the application instructions carefully, and maintain awareness of your surroundings.
Because PlayStation VR uses 3D vision technology, and it can affect people in different ways, they suggest trying it out at a demo event before buying one.

In the FAQ section, Sony says PlayStation VR can be played wearing glasses, but “there may be individual differences, basically users can play while wearing glasses.”
They also answered some questions about multiplayer and Cinematic Mode:

Can people other than the person putting on the headset play"

Through ?Social Screen?, users can play with family members and ...