Agent's will see Tymeshift in up to three places within Zendesk, the Top Bar App, the Tickets Sidebar App, and if you have the Zendesk Chat App installed, inside of the Zendesk Chat Sidebar App.
Here's what Tymeshift looks like to agents:
Top Bar App inside of Zendesk Support
Ticket Sidebar App inside of Zendesk Support
Chat Sidebar App (optional)