You can restore much of the look & feel of the previous version with these shortcuts:
- Ctrl-B to turn on the menu bar.
- Ctrl-S to turn on the sidebar.
- Ctrl-/ to tunn on the status bar.
- Click the magnifying glass top right and untick Search Entire Library to restore the previous search behaviour.
You can also open the menu bar temporarily by pressing Alt.
File > Add folder to library will let you add folders. You can still drag & drop folders into iTunes as before.