You can remove staff from a team all from within the App.
Open the App
Make sure you are in a team and a team admin
Tap the menu icon at the top left of the screen
Tap 'Members'
Find and tap the member you want to remove
Tap the ellipsis at the top right of the page
Tap 'Remove from team'
Confirm by tapping 'Yes'
The team member is now removed