You can invite any learner in on PRISM for a personal chat. Click on the ‘+’ symbol right next to People on the right-hand side and enter the name of the learner you wish to add. A request will be sent inviting the learner to chat with you. 
When a request is received, the learner can either accept or decline. If the request is accepted, you can start the conversation and if it is declined, another invitation has to be sent.
You can also update your messenger status which will be displayed publicly to other learners.