Submit first meter reading

Can anyone help me please? I’ve been asked to submit my first meter reading. When I login I’m faced with 4 green boxes ‘payments & statements’ ‘energy usage’ ‘account settings’ and ‘refer a friend’ I’ve click on all and none give me the option to submit a meter reading. The most obvious ‘energy usage’ says they do not have enough data to draw a graph and below is the section ‘meter readings’ that says no readings yet and there’s nowhere to enter them!! It’s driving me mad! Thanks