To set up Auto Top Up for your Clinic's credits, select the 'Credits' page in the Settings tab. From there, select the green 'Setup Auto Top Up' in the top right hand corner, within the banner that displays the credit balance.

To set up the Auto Top Up, first 'turn on' Automatically top my account like this:

Following this, select the amount of credits that will be set for your Clinic Auto Top Up:

Then, nominate the specific number of credits that will be the threshold for 'low balance' - when the credits fall below this number, they will be automatically topped up: 

Once you have completed all three steps, save your changes!