I think you used the wrong button. In the video, Ralf used Change Properties, but you write Edit Properties in your post, and that prompt is indeed the expected one if you use Edit Properties.

The change Properties and Edit Properties button do look a bit similar, so they are easy to confuse.

Thanks @Ricko, Heartglen is now in the atlas, and the area complete.

That would be the actual size of your world. As with any map, it is important to know how large it is before you start mapping. If you are mapping a whole world/planet you need to know the dimensions of the planet.

I find a good style that is designed for large scale mapping. When mapping a whole world, you would normally want a style where you can do most of the mapping using drawing tools and fills, and not overly rely too much on symbols. A lot of our styles can do this just fine, including the default overland styles that comes with CC3+, but some are better suited for more local area mapping.

Don't try to add too much details. I usually think of my maps like those found in the school atlases. A map couldn't be bigger than a two-page spread, so it should be readable at that size. Details that are too small to show up at that scale, or would overly clutter the map is left out, these can be shown on separate zoomed-in maps of relevant areas. I like developing my worlds as a series of maps of different scale levels, similar to what is done in the community atlas.

The reason for avoiding tiny details are twofold. First of all, it reduces clutter in your map and makes the map readable when you view it zoomed out. Secondly, filling out a whole world with tiny details are extremely time-consuming, and almost always leads to mapping fatigue and a half-finished map that never gets finished.

You don't have to reinstall the software. That preset is embedded in the map template, and can be regenerated from it. The preset is only needed if you need to re-apply it to the map for some reason.

To recreate the preset, start a new map using the right style, the CC3 Mike Schley Overland in this case using default settings in the new map dialog, then enter the :CC2SHEETS: dialog, make sure effects is turned on (otherwise the options are greyed out), simply hit the "New" button to create a new setting based on the current map, and name it CC3 Mike Schley.

That's a shame. But it is is up to you if you want to remake it or not, nothing else in the atlas depends on it, so everything else still works fine.