OS: Ubuntu 18.04 LTS
Files/Nautilus: 3.26.3
GNOME: GNOME Shell 3.28.1
Nautilus not showing mounted drives and Computer(/) in the side bar, but are visible in "Other Locations"
Is there some config file I can change or some settings I'm missing to achieve the aforementioned.

Best Answer
You need to bookmark them and will likely want to rename the bookmark. This GIF illustrates the technique: