Question: how to sync goqii band with app?
Answer: When you open your app, it will prompt you that you do not have a GOQii Band linked to your account. ... 
Incase you do not receive this prompt, click on the top right hand '+' Menu option.
Click on he words 'GOQii Core Not Linked'
You will be on the 'Devices' screen - Click on Button Link GOQii Band.