Also note that Pega Co-browse and the engine for Pega Customer Service's Chat feature are available as Cloud Only Services from Pega Collaboration Cloud.
Coming to some specifics of on the queries you have:
Both Co-browse and Chat work on Websockets protocol. Hence if some parts of these products/features (Co-browse Dashboard or Pega CS installation) are being accessed from behind a Customer's network security setup, Websockets protocol would need to be allowed within the network. We expect the customer's IT staff to know how to do this and we don't have expertise around it.
If you have the Pega CS Chat working on a Customer application and that allows usage of Co-browse, then the page already has the Co-browse JS needed. Co-browse can be started using the mode it is setup to start (details are in the implementation guide).
If the above is not the case, please refer to the implementation guide about how to include Co-browse in a webpage.