Ok. I figure it out. This is it what I did:
As per the troubleshooting notes "17. If you choose UEFI Boot Mode install, the USB stick MUST be formatted as GPT". It turns out that to format GPT you have to select the option "Scheme: GUID partition map" in the "erase" command on Disk Utility
The problem for me was that the scheme option was not available for my two of my USB sticks. Probably because both are by default MBR instead of GPT. I don't know how to make it work in MacOS (I'm a newbie mac user), but I know how to convert a MBR drive to GPT in Windows using diskpart.
If you have a windows PC available here is the procedure:
1. Open Command Prompt (press windows key and type cmd)
3.Type "Diskpart", press Enter
4.Type "List Disk" , press Enter
5.Type "Select Disk #" (where # is the number your drive shows up as), press Enter
6.Type "Clean", press Enter
7.Type "Convert GPT", press Enter
8.Type "Exit", press Enter.
The drive is ready in GPT to be formatted in MacOS with the "erase"in "Disk Utility" as show above selecting Scheme: GUID Partition Map.
I'm sure there should be a way to convert an MBR drive to GPT in MacOS that you can google if you don't have a Windows PC available.