Newbie winterization question

[Bcc75]

I have a new 2021 International 25’
It has a tankless on demand water heater.
I plan to do just the blowout method. We live in Ga so I think that would suffice.
Plus add some antifreeze to ptraps and tanks.
Does the water heater not hold anybody water any water in it’s internal lines?
I know you have to shut the Valve off to it if you pump antifreeze but since I don’t plan to to do that is there anything you do to it? Dealer told me there is no drain in it.
Also what’s the best way to protect the toilet bowl seal? Antifreeze or silicone ?

If anyone else does this and feels like giving me a walkthrough, I would appreciate it. Manuals are confusing.
Thanks

[Jrod]

I wondered if we have same suburban tankless hot water system? I have a AS Nest. With that in mind, I blew my lines water out with compressed air and accessed water system to turn red knob counter clock wise to "drain " water from system. The red knob also goes to right with sm click and soft stop. I kept air going with knob in both positions. I am not positive which was correct.
Do you have this system? I wondered what positions are which.
Thanks in advance..
J Roddy

[Bcc75]

Mine is a Girard water heater. I was told that there is no drain on it. If you just use the compressed air method then you just blow air through it as you are south the rest of the trailer. If you pump antifreeze then you shut the valve off to it to keep antifreeze from going through it. The Manual is not very clear and the winterizing instructions really do not mention it.