I had a few issues with this myself to begin with. Got there in the end with the help of @vasileios and others. Still sorting other things out. BUT…have you gone to the Beginners page? One of the links below in that which might be useful:
I’m erasing my first USB drive, to create a boot disk. in the instructions, it says I need to
“Give it a name and choose MS-DOS (FAT) under Format and GUID Partition Map under Scheme.”
I do not have the drop down menu for “Scheme”. I cannot select Guid Partition Map. Do you think this matters?
Also, I am going to prepare several drives before I actually remove Apple from my Mac. The Linux Mint download page gave me the option to download the Torrent? I don’t know what a torrent is, but a general search says it’s like a table of contents…
Hope it went well and you’re all sorted. I wasn’t able to do the Partition aspect either from memory. Got there fine .
Fingers crossed by now you’ve been able to check each one out and choose the one you like best