Which Grundig SW radio is it? Some Grundigs have the SW broadcast bands programmed into them. You hit a couple buttons and it switches you to a band. I have a Grundig that will toggle up from one SW Broadcast band to another.
For a new person to SW, the SW broadcast bands are like several MW/AM bands placed in different areas of the SW spectrum. If you look at it that way, it's a little easier to understand. They used to almost be as crowded as the MW / AM band is at night. But over the years, a bit less so...