You're at the right place and welcome. Also, Winnieowners' sister site, IRV2.com, is a good place as well, especially for non-brand specific issues like towing a toad, etc. If you create a habit of perusing new posts every day, you'll learn a lot in a couple of months. Many of the forums have set of "stickies" that contain a lot of good info. Here are some:
You should also set up a signature like mine that lists your year, model, length, etc. You can do so via the User CP tab on the toolbar. That way, responders can be more specific to your rig and you won't have to enter it each time you post.
With respect to your city water fill issue, read your manual, I think you'll find there's a valve setting for filling from city water vs. just using city water (these valves can be confusing). If you don't have the manual, you can download one from Winnebago.