Please open this link: http://uzzu.tv/member/default/index/order on your phone/pc web browser and then rearrange the channels. The same order should automatically reflect on your Firestick app.
So essentially you are going to do everything on your phone/computer and it should automatically be applied to your Firestick Uzzu app.
 

If you run into any issues please send an email to support@uzzu.tv