Everyone says sequence diagrams are so easy but I just cannot figure this out. Basically user clicks on an 'Import from temp folder' button, the program opens a window with a list populated with filenames, user clicks on a filename, clicks on OK and the document is imported. I know the order of the actions but how to depict e.g. populating a list, or selecting an item from a list?

So I assume the objects would be like:

[USER]  [ImportDialogWindow]    [ListOfFiles:STRING]   [?where to go with selected file]