User blog comment:Militemus/Help With Profile and Icons/@comment-31777410-20171005185559

for the  userboxes:

classic editor > source -> type –  -> and write something from this list inside the brackets (e.g.   ).

It should look like this:

for the icons:

go to a page, and download one of the icons in that page (e.g. germany-icon.png)

recolor it with your flag's colors and use paint.net to make it transparent