Welcome to the forum and to SE Writer of course.
I have a pretty good guess what is going on, but let me start the other way round.
When you wrote, you “figured out” how to import your existing work from a word document, I sensed you may not have the user manual downloaded or came across the [online] Knowledge Base either.
The Knowledge Base has everything to help you to work with SE Writer. That includes importing your Word documents too. So, you don’t have to do a trial and error style to figure out how to do things.
At the very top of the Knowledge Base is a link to the user manual (PDF). It’s the same content, the Knowledge Base offers, just as an offline PDF version, which opens with nested bookmarks on the left. That’s where you can easily find any ‘How to…’ info.
I copy the URL here for you: https://www.smart-edit.com/Writer/Knowledge/
As for your problem, I suppose you tried to copy right away into a folder on the left side. That does NOT work. See any folder just as a container where you can put notes or scenes for example.
I assume you have the ‘Project’ tab at the top navigation selected. Highlight and double click the folder where you want to copy your text to, then click on ‘Add Scene’, ‘Add Note’, or ‘Add Folder’. Whatever you selected will be created within the folder you chose.
Then you can copy everything into that newly created ‘whatever’. I guess you’re familiar with Windows’ standard combinations of Ctrl+C for copying and Ctrl+V for pasting content. It all works here in SWE the same easy way.
Needless to say that you can copy and past on the right side in your Notes column as well.
One more note for your convenience. When you pull SWE up, it starts with the Project Manager. One already installed [and shown] project in this list is ‘Huckleberry Finn’. There is a reason for that. Darren, the developer, created the project as an example, showing everything that SWE does. Clicking through this project gives you the ‘oooh, that what it looks like’ effect, and may be a good idea as well.
Hope that helps,
Addendum: I missed the part where you write you tried to copy from withing SWE, and were not able to. Sorry about that.
Question? Did you just highlight the target (note or scene)? That doesn’t open it. Double click the traget scene or note. It will mark the active one with a little red checkmark as open. Then copy your text. Maybe that’s what was missing in your attempt to copy internally.