Unassigned Devices Plugin
Unassigned Devices (UD) includes a lot of functionality and has become a bit complex. Please read the first and second post. You will find answers to most of your questions.
Note: You will need to install the Unassigned Devices Plus (UD+) plugin to enable HFS+ and APFS (Apple file formats) and exFAT (flash larger than 64MB) disk mounting, and to enable 'Destructive Mode' for formatting of some UD supported disk formats.
UD and