6 years ago at a new job I was forced to use provided Mac laptop. Never used MacOS before.

So first thing first: get Firefox. Managed to download .dmg file. Double clicked it.

And now I see utterly confusing window with an image that tells me that I need to move downloaded Firefox to applications to use it. Where I am supposed to get the thing that I need to move? Totally not clear that the icon in this window is interactive and can be dragged. Why can not it do this thing by itself? At which point association with handling http links will be configured and whom? How am I supposed to figure out that dmg is like a zip archive?

I was completely lost until colleague showed me what I was supposed to do. I burst into laughter when he showed me. I don't think he understood why.