Appliance Repair Questions? Ask a Technician for Answers ASAP
Hi, thanks for using JustAnswer.com. You will not need to turn the water off and you will want to run about 2 gallons of water through it to flush it out and remove all the air from the system. As far as installation, please post your model number so I can see exactly what filter you are trying to install.
The manual is below. Page 15 gives instructions on replacing the filter.