Like I said we don't know each others skills, but I have been doing this type of work for many years. I can only give you some words of advice. Take your time and only work on one circuit at a time. Use your wiring diagram as a road map and when you come to a switch ( all a relay is, is a electric switch) stay with the circuit you are working on. Do not repeat work which is very easy to do. You will come across and see the problem when you get there.