Mount host folders in Ubuntu guest OS

Open Virtualbox Shared Folders settings, add folder, make note of the Name.

In Ubuntu guest OS, create folder wherever (only needs to be done once): mkdir ~/Desktop/Host
Check your id by doing: id
Mount the folder using your uid and gid: sudo mount -t vboxsf Name ~/Desktop/Host -o rw,exec,uid=1000,gid=1000,dev
If you want to unmount later, do: umount ~/Desktop/Host