please help, wireing harness
 

i have focused the problem of my
radio
digitalclock
gague lights
interior lights
power locks
running lights
and tail lights

all going out to my wireing harness, maybe a short made from installing a new radio?

I looked under my dash where is kind of hangs, its not factory installed im sure

I want to just replace it all toghether

2 questions

1)where can i get a wireing harness?

2)can i install it myself?