The distribution panel you are buying is intended for 50 amp service available to plug in. Multiple breakers allow you to distribute 120v power on separate branch circuits.
The 12v distribution side includes a 90 amp converter to supply 12v to the RV lights and accessories. In addition it will charge your battery when you are plugged into electric power from utility or generator power.
This system works in conjunction with the solar or alternator to keep the battery charged.
No inverter.
Maybe post what you are attempting to accomplish so this can be confirmed or redirected to some other equipment.