To connect an A2 to your account, tap the Connect tab. First of all, make sure that Bluetooth is enabled on your iPhone/iPad.  Start your A2 by attaching the battery to the battery connector on the A2. 

Next, plug in a USB cable connected to a charger/computer/etc. 

Now tap the + button in the top right corner and choose Scan for unit. Make sure to hold the A2 close to your iPhone/iPad. When the app finds the device, it will be displayed as in the image below. When an A2 is added to an account, it can’t be added to another account.