Victron Multiplus II GX charge/cheap electricity price discharge/high electricity price

Hi,

I have multiplus II 3000VA GX model and TAB ESS Rack e.Module L5.1 51,2V/5kWh.

I want to use my system as UPS backup and Battery storage when elecrticity price is high and charge battery when price is cheap.

I am using HomeAssistant and I have sensors when price is cheap to charge the battery and when price is high to discharge the battery.

But what commands should I send to GX mqtt broker when I want to use my load from battery and what command to recharge the battery.

I am not selling electricity to grid. and I want to keep 40% off my battery for in case off grid failure. Allso no solar panels at the moment.

My power consumption is about 600W from the inverter.