To top-up credits, select the "Scan" button and then choose "Top-up Credits". You will be redirected to the Top-up Credits Page (Page 1 below) where you can select the denomination or type in a different amount. 

After selecting the amount, you will then be asked to select the payment method (Page 2 below). Tap the guest NFC Tag at the back of the device to complete the top-up process (Page 3 below). 

Users may also check the guest's remaining balance by going to the "Scan Page", selecting "Manage Tag" and the guest information, Tag UID, and the remaining balance will show up as shown in the Manage Tag Article.