For Ubuntu users who are accustomed to have window ‘close, minimize, maximize’ buttons on the left side, this simple tutorial will show you how to move window buttons position after you install or upgrade to Ubuntu 20.04 Focal Fossa
1. press alt+f2
type < and press enter
2. when Gnome Tweaks window pop up, navigate to Windows and titlebar tab. At the bottom, you can see the toggle to change the titlebar-buttons (right or left) placement.