I&C:- Installing means just install any device or machine in without working condition. commissioning means to run that same machine or device that was installed. to convert that dead machine into working condition properly according to the desired parameters on safe condition is known as commissioning.
Commissioning is the process of planning, documenting, scheduling, testing, adjusting, verifying, and training, to provide a facility that operates as a fully functional system per the Owner's Project Requirements.