Zoom meeting

Someone sends me a zoom link to join, when I open the link, it shows the zoom page with the Launch meeting button. I click on the button and instead of launching the Zoom app, it downloads a .dmg file that does nothing. Clicking on the file opens the mac installer where it directs you to open terminal and drag file into terminal. this only ends up in a Volumes folder and that's it. No meeting launched! 
what do I do?