Snapping (so called)

Hello,
In the lower toolbar, above the timeline,
there is a symbol of a magnet, horseshoe shape.
What is it for and when and how to use it. (Demo please, if possible).
Answers will be appreciated.
Thanks
Motim

Shotcut version 20.09.27

With Snapping on, clips on the timeline automatically lock to another clip or the playhead when it is moved near it. This is especially useful if you want to place clips one after another without leaving any gaps.

There are times though when you may want to move a clip to a specific spot but because there are other clips near the snapping may make it difficult to place it in an exact spot. So in that case it is useful to turn snapping off.

Demo in docs here