Pic of a PD 4655

Am I correct in thinking that it replaces a PORTION of one or more popular Makes/Models of Converter/Charger?
We have an IOTA that I'd describe as All-In-One. It's OEM, no doubt cheap, and it comprises:
AC Breaker Panel
DC Fuse Panel
Power Converter 120VAC >> 12VDC
House Battery Charger
I can DO Wiring, Cutting, Fitting, Trimming. I anticipate a total nightmare swapping out the IOTA because all the related wiring is cut short. I can barely replace a Breaker let alone connect the wiring we have to a new unit with a different layout.
How do I get that done?