the first thing for you is to try a haynes manual! these have wiring diagrams in them!

regarding the door light this is almost always an earthing fault due to corrosion / dirt around the door open switch, try cleaning wilth a dremmel! also try grounding the wire there and see if that works.

check the microswitch and see if it is open or closed circuit normally then make it the other for a test with the 2 wires! the 3rd tail could be as the switch is a 2way switch and the connector is on the wrong way!

the boot light will need checking with a volt meter and might be related to point 2!

good luck!