If you have a Zoom meeting link/url but need to join the Zoom directly from the Zoom App, here's how:

You must have the Zoom app installed before using these methods

Method 1

Video demo

1. Make sure you have the Zoom app on your device
2. Open a web browser (like Chrome)
3. Use the keyboard shortcut to open an incognito/private browser window:
   1. Window: ctrl+shift+n
   2. Mac: cmd+shift+n
4. In that incognito browser window, paste the Zoom Meeting URL (something like e.g., https://stonybrook.zoom.us/j/12345678911?pwd=abcDefGhiJKLMnopQRSTuVWxYz)
5. When prompted, click Open zoom.us.app
   
6. The Zoom meeting will open in Zoom

Method 2

Video Demo

1. Open the Zoom app (learn how to download and sign into Zoom app)
2. Click Join
   
3. The URL has 2 parts in it: Meeting ID and scrambled passcode. You'll need both to enter the meeting. 
   
4. In Meeting ID or Personal Link ID box, paste the whole URL and click Join (something like e.g., https://stonybrook.zoom.us/j/12345678911?pwd=abcDefGhiJKLMnopQRSTuVWxYz)
   The box will automatically show the Meeting ID part of the URL
   
5. When prompted for a password, paste the scrambled passcode (the part of the URL after "?pwd=") in the box and click Join. (the passcode is abcDefGhiJKLMnopQRSTuVWxYz in this case.) 
   hint: paste the whole URL into a text document and copy out the part after the ?pwd from that document