Okay. Make sure the body you order has the 24 fret Neck Pickup position moved, or it'll interfere with your pickup.
Tuning machines - hold the strings at the neck end, and provide tuning capability
Neck plate - holds the neck onto the body
4 Neck screws - holds the neck onto the body
2 Strap Buttons - so you can use a guitar strap
Bridge (TOM/STP is common for LP bodies) - the other end of your strings lives here
4 potentiometers - the things that your knobs control (volume, tone) can make them louder, quiter, etc.
4 vol/tone knobs - what your fingers touch to manipulate the potentiometers
2 pickups - i hope you know what pickups are
3 way pup selector - chooses between what pickups are 'on'
2 pup rings - to hold the pickups onto the body
wiring...wires - to make all the electronics work
output jack - so you can plug in a cable
6? misc screws for control plates on back - to hold the covers on