It is the same command which is triggered no matter if you use Ctrl+C, pick from the menu, or the button right click. All of that are just simple shortcuts to the same command.

But for copy, it is important do follow the advice from @Wyvern about waiting till the command actually finishes and the selection indicators disappear, only then is the command done and the contents on the clipboard. And equally important is it to actually finish the command, a lot of people forget to pick the requested origin point after hitting Do it, but if you leave out that part, the command isn't done, and nothing will be copied to the clipboard. (Always pay attention to the command line)

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.

Looks like there are a few .symfill files missing from the install, so it defaults to the standard escarpment config, and the default there is a line symbol....

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.

Note that if a layer won't freeze, it is probably because it is the active layer. Make sure to set the layer you want to work on as active first (The first checkbox), then you should be able to freeze the other layer.