Here is the thread
for winterizing has pictures showing by-pass valves.
You may access beside tank in a compartment below or behind wood panel -bathroom or kitchen.
You can drain tank by removing metal nut bottom front of tank and also check the anode rod and see if you should get a new one also open the vent top of WH to allow air into tank. Make sure you close vent so next spring when you fill tank there will be a expansion air space at top of tank.
You can just drain everything using low point drains but if you in a area where temps stay low may want pink stuff to protect you elbows, toilet fittings, faucets, showers inside and out.
Blow out lines maybe all you need, do not forget the washer area if you have the plumbing.