Your text frames are made to incorporate texts. Until now, we have mainly used sample text or have written the text ourselves in the frames. Sample text (Insert | Sample Text) is great when you want to work on the layout and you don't have the final text. This way you can look for the right and nicest settings, save them, and when the final text will arrive, add it.
Most of the time, you'll import the text from another file. There are two reasons for this:
Scribus is not the most handy tool to write text: text editors or text processors will do it faster and in a simpler way.
You may not be the author of the text, and other people don't have to care about the layout, just the content. Only you will need to deal with Scribus and you'll receive text of other file formats. Of course, you should not modify the authors' text without their agreement.
Importing text is very simple but the procedure can be different regarding the file format you use. Some file formats will use...