To communicate with a Hirer, all Team Members (including the Team Lead) could use their Workstream's built-in Instant Messaging (IM) application.
To do this, you need to click on the MESSAGES tab in your Project Workstream and then on the left-hand-side menu of the IM box, you need to click on your Team's Username or ID. Compose your message in the box provided and click Send.
The Hirer, as well as the rest of the Team will be able to view and respond to your messages.
Please note, group messages are visible to all Team Members as well as the Hirer. If you wish to communicate with a specific member privately, you need select that Member's ID from the left-hand-side menu of the IM box (under the DIrect Chats section), and compose and send your message to them directly, instead. Private messages are visible to you and the designated member, only.