Administrative law is comprised of the regulations, rules, orders and opinions issued by administrative agencies.
Administrative agencies promulgate regulations to clarify how a law will be carried out and enforced. Regulations are published chronologically in a Register, and published by topic in a Code.
Agency can have any or all of the powers of the three branches of governement.
This is determined by the agency's enabling legistation.
To find out what powers a particular agency has check out the government manual or the state equivalent.