The upper body is currently under construction. So far, the LED wiring is personally the most difficult part of the PGU kit for me (;´д｀)
I'm being very careful because I'm worried that the LEDs might not light up after snapping the parts together and then testing them.
However, I've found that the parts separator included with the LED unit is quite useful for disassembling the temporarily assembled parts.
I should have opened the LED unit from the beginning.

PGUν Gundam Production Diary (15) | ハリ's Gunpla works