I would like to dedicate this short how-to assign/set default apps on Windows 10 to Chris Beard, who described the process as:
“It now takes more than twice the number of mouse clicks, scrolling through content and some technical sophistication for people to reassert the choices they had previously made in earlier versions of Windows. It’s confusing, hard to navigate and easy to get lost.” source: An Open Letter to Microsoft’s CEO: Don’t Roll Back the Clock on Choice and Control (The Mozilla Blog).
Step 1: Click on ‘Windows icon’ on the taskbar at the bottom left corner of your screen.
Step 2: Click on ‘cog icon’ labelled ‘Settings’, a ‘Settings’ dialog will appear.
Step 3: On ‘Settings’ dialog, Click ‘System’ item, to load ‘System’ settings dialog.
Step 4: Click ‘Default apps’ tab in ‘System’ settings dialog.
Step 5: Scroll down until you see ‘Web browser’, Click on the icon labelled ‘Microsoft Edge’.
Step 6: Choose browser from popup selection dialog.