AndyCarPVBattery
Firstly, from the WW menu, go to Settings, and fill in all the details about your system there. You'll need a token/API/key (whatever growatt call it) from your system to enable WW to communicate with your inverter.
Don't forget to save at the bottom of the page.
Next, from the WW menu, go to Octopus, Intelligent, and fill in. You need your Octopus acc.no. and API key.
Toggle some buttons to suit what you what to happen with you inverter/batteries.
And save again.
I GE, rather than Growatt, so hopefully someone else will chip in to help with any specifics for yours.