There's a huge hole in the advice, and it's the how, the why, and the when. So let me actually fill it in. B-roll has a job. It is not decoration. It's there to do one of a few specific things, and if it isn't doing one of them, it shouldn't be in your edit.
Show what someone is talking about
Person mentions the busy workshop? Cut to the busy workshop. Now I'm not just hearing it, I'm seeing it. The B-roll earned its place.
Hide a cut
Got two takes of someone talking that you want to join? A well-placed B-roll shot over the join makes the edit vanish. The viewer follows the visual and never notices you stitched two clips together.
Set a mood or a place
A few atmospheric shots of the location, then into the content. That's establishing, and it works.
What B-roll should never be is random pretty footage shoved in to look busy. If a shot doesn't show something, hide something, or set something up, cut it. A tight video with three meaningful B-roll shots beats a messy one with thirty that mean nothing.
Purpose first. Pretty second. That order, always.
What will Kumar do?
When I cut your footage, every B-roll shot has to earn its spot. I'm not padding the timeline with random clips to look fancy, I'm using each one to show something, smooth a cut, or set a scene. That's the difference between a video that flows and one that feels stitched together from a stock library. I'm a video editor in Calgary and I treat B-roll like a tool, not a garnish. Hand me your footage and watch it actually come together.