[itsme]

Create the collections first. Open the respective collection, then import your song files. If you import from an open collection the imported songs are automatically added to that collection.
You might try some settings in the "Import Settings" window. "Guess Title From Filename" does what the name says. If you set the checkbox "Load song editor after import" the "Import Settings" window is opened after a successful import for further edits. "Automatically crop pages" is very helpful for importing PDFs or images.
Just play around a bit and check what is useful for your specific needs