The reason why I didn't make serious mistakes was I keep my digital camera handy with me while going through with the car repair. I took pictures every step and whenever there are steps that I am not familiar with.
My advice to others when going through the same process I went is take pictures and be careful with the wiring harness if they are still okay. Avoid bending them. You will ruin the insulation. You will find out if you open the black cloth tape cover.
94 E320 Silver 210000 miles
94 740il Pewter Green 97000 miles- Retired
05 S430 4Matic
07 Lexus IS250