Good morning

I have been given a spreadsheet and, while I can see what the formula does, I don't understand how it is working. Can somebody please explain, step by step?

=(IF(C139=0,,C139&"
")&IF(J139=0,,J139&"
")&IF(K139=0,,K139&"
")&IF(L139=0,,IF(L139=M139,,L139&"
"))&IF(M139=0,,M139&"
")&IF(N139=0,,N139))

C = Name of store
J = Address1
K = Address2
L = Town
M = County
N = Post code

Many thanks