Team Assist is enabled per team. Agents only have access to Team Assist if they belong to a team with the feature turned on. As an admin, you can control which agents have access and configure the shortcut buttons they see when they open Team Assist.
Enable Team Assist for a team
Go to Settings and select Teams under People.
Find the team you want to enable Team Assist for and select it to open the edit view. You can also create a new team if needed.
Under Enable features, check the Team Assist checkbox.
Select Save.

Repeat for each team that should have access to Team Assist. Agents who belong to multiple teams only need Team Assist enabled on one of those teams to access it.
To remove access for a team, uncheck the Team Assist checkbox in the team's settings and save.
Configure Canned responses
Canned responses are the shortcut buttons agents see at the start of a Team Assist session, before any prompts have been sent. Two buttons are included by default:
Catch me up: Summarizes the current Conversation: what the Customer needs, what's been done, and where things stand.
Summarize this customer: Gives a quick summary of the customer's profile, preferences, and past interactions.

You can add custom buttons for prompts your agents use frequently. Each button has two parts: a label (the text that appears on the button in the workspace) and a message (the actual prompt sent to Team Assist when the button is clicked).
Manage Canned responses
Go to Settings and select Team Assist under Agent Experience.
The Canned responses section lists all current buttons with their label and message.
To add a new button, select Add response, enter a label and a message, and save.
To edit an existing button, select Edit next to it, make your changes, and save.
To remove a button, select Delete next to it.

You can also select Browse library to choose from a set of pre-written prompt options.
Tips for writing effective button prompts
A button's message is the actual prompt Team Assist receives, so the quality of the prompt affects the quality of the response. When writing custom button messages:
Be specific about what you want Team Assist to do or return
Write the message as if an agent were typing it themselves
Test new buttons with a few real conversations before rolling them out to your team