The house itself is pretty straightforward; each section has a connector that joins it to the electrical system, and you run power to the panel as you would a regular house, only from a pedestal you set. The PoCo connects to the pedestal.
Now, the pedestal is where it can get tricky. The PoCo will likely want the trench (for UG feed) a good 5 ft. deep. You will need a ground rod, and make your bond in your section- not the PoCo pull section.
In practice, I suppose that the house itself ought to have a ground rod as well; though I'm not sure I've ever seen one!
In my part of the world - all thats required is the basement work. Install panel that is provided with the house, stub out some SE cable, (POCO does all the meter work in my part of the world) Drive ground rods, bond service , wire basement for lights ,receptacles, well, furnace/heat pump, water heat etc etc
The ones I have done have required splicing boxes in the basements. The basements are actually at ground level. These were townhouses with 1 car garages. There's 6 sections (3 sections per floor), 2 floors, with tails down to the basement that either went as homeruns or to complete 3-way switching between any of the six sections. Basements had 1 bath, garage, hallway, laundry area, utility room and one large liveable room.
They're near impossible to do without owning a toner. That would be the advice I would give, have a toner and if u don't have one, get one.
We have some canadian units come down here with A stub down for the panel like a mobil home with the panel in the middle of the house. Except there wired for a 3wire service.If they were placed on a basement the best thing to do is install a regular service in the celler and run 4 wire to the house service and seperate the grounds and neutrals and treat it like a subpanel. Then wire all the celler and utilities from the celler service. The prewired panel probably doesn't have any spare spaces anyway.
Namely if the modules are built to be assemled into a permanently sited home, or later disassembled and relocated, AKA trailer home.
Around here, there are two manufacturers of the former, which are connected to service as a site-built home, with a the meter socked directly attatched, with a 3 wire feed and bonded/earthed in the home.
Around here a modular is the same as a stick built house. Meter on the side, longggg tails hanging for the homeruns that we just drop at the panel which we put wherever we want. Basically it's a house that mostly needs service work. Now a Mobile home (i.e. trailer) is another story.