To send a payment with Vivi is very simple.
Go to the accounts screen
Tap 'Pay'
Tap the + icon on the bottom middle of the screen
Tap 'Send'
Tap the + Icon in the top right of the screen
Select the method of payment (Bank Transfer, PayID or $ViviTag)
Enter the recipient details
Enter the amount
Press confirm!
Thats it, very simple!