Please help, I know it is not hard, however I want to make sure I don't mess this up.
How do I drain/flush water heater and check/replace anode rod?

Check in our technical library. There is a section with manuals and it includes the Suburban Hot Water Heater with a description of changing the anode. Stick a small hose into the hole where the anode rod is removed and flush the debris out the same hole. Camco make a special plastic flushing tube that makes this easier.

Here is how I do it.

Most important is to ensure that the heater is turned off on the 120V side, there is a switch on the back of the heater itself and I also throw the breaker off, you will kill the electrical element if you drain the water with the 120V power on (don't ask me how I know!).

Open a hot water faucet to release some pressure after ensuring the city water and the pump is off. Use a socket wrench or a standard wrench (socket is easier) to turn the drain/anode slowly, let the water drain out then remove the anode.

Purchase a water heater flush tool at Camping World or your local RV dealer and flush out any debris.

Clean the anode with a wire brush, replace it if it's left with only a wire or small diameter.

Using the wire brush clean the threads of the anode then put a few layers of teflon tape on the threads, I've found more is better than less to stop leaks.

Use the socket wrench to tighten the anode, tighten enough to stop leaks but don't overtighten. Connect the water or pump water into the RV, when you hear the flow stopping indicating the WH is full re-start the WH and do a final check for leaks at the anode after the water is hot, tighten if necessary

Also flip the little metal handle on the high pressure relief valve to drain for a vent & leave it open while filling to insure tank gets full, this also confirms valve is not stuck. Turn heater off a few hours prior to draining, the water is damn hot.

I looked on Amazon there are two.
1. Suburban 232768 Aluminum Anode Rod price is $13.87
brand Suburban
Item Weight 2.4 ounces
Product Dimensions 9 x 0.6 x 0.8 inches
Origin China
Item model number 232768
Discontinued by manufacturer Yes
Manufacturer Part Number 232768

2. Suburban 232767 Water Heater Anode Rod Price is $15.24

Brand Suburban
Item Weight 2.2 pounds
Product Dimensions 1.9 x 0.8 x 0.1 inches
Origin China
Item model number 232767
Manufacturer Part Number 232767

I'll be replacing my next anode with one of these...

I will be modifying it to include an extension pipe and small valve. That way, every time I drain the unit, it will drain "outside" the RV instead of soaking the side panels. What a dumb idea they have...

Just a hint: If you don't wish to turn the water supply off, as someone inside might be using it. If you place the water heater bypass control into bypass, you can leave the main water on.

I'll be replacing my next anode with one of these...

I will be modifying it to include an extension pipe and small valve. That way, every time I drain the unit, it will drain "outside" the RV instead of soaking the side panels. What a dumb idea they have...

I have serious doubt that once that corroded you won't be draining through it. Also once drained & removed you will still have it running down the sidewall while flushing it out.

BTW that's for an Atwood heater, yours is a Suburban.

I'll be replacing my next anode with one of these...

I will be modifying it to include an extension pipe and small valve. That way, every time I drain the unit, it will drain "outside" the RV instead of soaking the side panels. What a dumb idea they have...

I have serious doubt that once that corroded you won't be draining through it. Also once drained & removed you will still have it running down the sidewall while flushing it out.

I replace them once a year anyway. So far, they are not that corroded. The extra stem length would keep the side wall dryer. I'm tired of taking a bath every time I pull it out.

If you leave these in too long, the threads get galled up. Then you're lucky to get it out. It's just cheap insurance to replace annually. I also get to flush the tank when I do this. It's amazing how much crud accumulates.