The Magnum should charge automatically though we speak of "3 stage" converters and chargers there are really 4.. I will cover
BULK (Automatic) this is a rapid recharge of a battery that has been rund own some The idea is to bring it up to around 90% State of charge QUICKLY. assuming batteries are at 50% soc and your converter's output is about 1/3, in amps, the 20 hour Amp Hour capacity of the battery. this stage should take about 2 hours More battery, or less charger, Extend the time.
Absorption: This is a much lower current, as little as a few percent, Takes about 3-4 hours. IN this stage the batteries shoudl reach 100%, this stage too is automatic
The final automatic stage is FLOAT, roughly 13.6 volts, lasts forever, in this stage the batteries are full, we are just keeping them that way and the converter is providing all the operating needs of the RV.
The above stages are automatick the converter switches from one to another with out human assistance (some can be "Forced") but you need do nothing to switch as needed between modes save feed it power and as someone up-tread said 15 amps (Standard house outlet) via the proper adapter(s) will do the job.. I( spent about 2 months at a repair shop recently eating 15 amps just to the converter.
The 4th Mode is Equalizatin and that one, rarly needed is usually invoked MANUALLY, that is the only one you must request.
The mode is only needed when the cells measure differently on your hydrometer. IT is a controlled OVERCHARGE designed to bring ALL the cells up to 100% SOC or better, overcharging boils off some of the water that makes up the water/acid mix on cells that do not need all that much charge, but hopefully it will bring them all up to 100%, that is Equalize them.