Link a button to a list

I have an option list where the user can select an employee, complete the sign in process, and their name and the employee’s name appears in a waiting queue. The list of employees are in an app variable

I want to remove the option list and have the user click on a button with the employee’s name and complete the sign in. The button works however its not adding the employee’s name to the waiting queue. All of the other information appears. The app does write to Firestore with the sign in information before updating the queue. Somehow I cannot link the button to a specific name from the app variable

Any ideas on how or if I can link a button to