To add a new user to AttendanceBot you need to first add that user as a member of the Microsoft Teams Team where the bot is installed. If you're a team owner in MS Teams, you can add someone to a team directly. If you're not a team owner, you can still follow this process to submit a request which team owner can then accept or deny it.
Step 1: Go to the team name in the "your teams" list and click "more options" ellipses at the right. Select "Add member"

Step 2: Start by typing a name, distribution list, security group, or a Microsoft 365 group. You can also add people outside your org as guests by typing their email addresses.
Step 3: When you're done adding members, select Add. You can make someone a team owner by selecting the down arrow next to Member.

Step 4: Select Close. People that you add to a team will receive an email letting them know they are now a member and the team will appear in their teams list.
Once done AttendanceBot will be able to acquire that new user For more information about activating and/or inviting new users once added to Microsoft Teams, read this article.
Note:
- Do employee profiles need to use the same email domain, or can personal email addresses also be included in the employee group?
AttendanceBot automatically syncs user profiles from MS Teams and picks up the email ID associated with the account.