- Open Preferences dialog, by clicking Edit -> Preference. See picture 1.
- In first tab select the lowest option Show only folders
- In the second tab select Always open in browser windows. See picture 2.
Picture 1: Nautilius Preference dialog, View tab.
Picture 2: Nautilius Preference dialog, Behavior tab.
If you want more extensions to Nautilius, check out the Nautilius extensions page - https://live.gnome.org/Nautilus/Extending.