Welcome aboard!
You are about to become an electronic technician.
No juice, no lights is not the charging system but a wiring, connection issue. "somewhere"
A couple pics of the bike will really help us, all stock or "re-engineered"?
Start by looking at connections.
#1 Ground strap from battery to frame. Remove, flex, looking for gray dust at the ends, clean frame reinstall.
#2 The the fuse box area is next, seldom intact by now, the little metal fuse holders rot and fall apart.
A simple diagram of the basic wiring.
View attachment 237929
the physical fuse box layout
View attachment 237930
power goes from battery to main fuse ,then up to ignition switch, (the switch CAN have corrosion issues inside) Hawaii, salty air....., then; back to fuse box to the other three fuses.
start at the battery and test till you find where the power peters out.
a good idea to print this out.
View attachment 237932
Poster size is handy....