Water Filter Installation. A few tricks and tips to make your bathroom installation a whole lot easier. See how to connect the pipes and fittings to the kitchen sink, sink, toilet water lines using PEX water lines and PEX fittings. How to install a drain system, different ways to configure it for your own situation.This is the BEST plumbing solution for beginner DIY plumbers. In this bathroom training video you will learn how to use PEX and copper water lines and fittings to quickly and easily plumb your new bathroom! Bathroom Plumbing is simple to do if you have the right instructions to follow. Watch this diy bathroom plumbing video and learn a few Pro secrets for getting your sink water lines installed right the first time.