So here is how to access your shared folders on Ubuntu VM(Oracle Virtualbox). Am assuming you have already enabled auto-mount while you were adding the folder.
Open the terminal and type.
sudo usermod -G vboxsf -a $USER
This command appends the current user to the vboxsf group, which is the owner of the shared folders (found in /media/ on the Ubuntu box). Confirm from your media folder if the shared folders are present. They're usually named "sf_name-of-shared-folder".
For quick access, you may want to create a link to the shared folders in the home folder.
In Terminal (assuming that you are in the directory where you want the link to appear and that you've enabled the Nautilus plugin that gives you the context menu option ) do:
ln -s /media/sf_shared/ name_of_link.
Replace sf_shared with the actual name of the shared directory and name_of_link with whatever you want. However the name-of-link shouldn't exist in the directory where you want to create the link(That is there should be no folder or file with that name). Alternatively, you can just drag the folder in Nautilus to the right navigation area and it will create an easy to access link.