What have you done so far?
What do you think you need to do?
Have you used the search tool for:
Primary secondary piping
control second boiler
There is lots of information here
maybe you should simply start with some light reading on the subject
You are going to have more questions then answers very soon - maybe already. Here is the best advice I can give you - Buy - rent - or borrow these books - Sit down and READ them and then lets chat. This is likely the best 80 bucks you will ever spend on your hobby!http://www.heatinghelp.com/products/Sup ... h-The-Flow
add this and your a jump ahead for wiring
This link is broken, either the page no longer exists or there is some other issue like a typo.