Pi3B: Error w/USB SD Flash drive/ Where do USB drive live?

[bubblegumpi]

I just tried to plug a USB to micro SD adaptor into my flash drive. Its a 4Gb flash drive with some windows files on it. I'm almost positive I have tried this before and got it to work, or maybe I'm on crack. I'm trying to access some .jpgs. I get this error pop up when I plug it in:

Error mounting /dev/sda1 at /media/pi/8B0F-C9ED: Command-line `mount -t "exfat" -o "uhelper=udisks2,nodev,nosuid,uid=1000,gid=1000,iocharset=utf8,namecase=0,errors=remount-ro,umask=0077" "/dev/sda1" "/media/pi/8B0F-C9ED"' exited with non-zero exit status 32: mount: unknown filesystem type 'exfat'

My other question is when you do plug in a USB flash drive where does it live? Some places say it's "/dev/sda" some say its in "/media/pi/" I'm trying to learn the GUI and the command line at the same time. When you plug it in does it create a new folder like it does in windows file manager? Or do you have to set up a directory for it to work? I plugged in a hard drive to the USB port with windowsOS and whole bunch of other files on it and just started saving files to it no problem. I would think this would be simpler.

[ghans]

Harddisks and all other filesystems have to be "mounted" on
Linux systems. That means partition/filesystem contents
(/dev/sda1) will be exposed at a mounpoint (a regular
directory e.g. /mnt/mountpoint_name).

Mounting can happen manually (via commandline "sudo mount"
command), semi-automatically (via entries in the "fstab" file ,
/etc/fstab which will be processed on bootup , the fstab
usually gets created once automatically and has to be modified
by hand if neccessary later) and automatically (via an
automounter) in an GUI enviroment.
Especially GUI automounters like to choose
directories under /media as mountpoints.

Your real problem is that your stick/card is formatted in
the rather new ExFAT format instead of say , FAT32.
You need to install the ExFAT driver. I believe you just
need to apt-get install exfat-fuse.

ghans