OEM stands for Original Equipment Manufacturer. When installing linux mint this usually mean the person installing it is intending to install the operating system for another user ie a shop technician installing linux mint for a customer. The install process is much the same except instead of setting up the first user , the installer sets up a temporary user as shown below
When the installer reboots into the install they can do a variety of tasks to get the computer ready for the person whom they are installing for this could include the following
Choosing a local mirror:
Install Programs From Synaptic
Since that is for the temporary user the file $HOME/.config/autostart/conky.desktop file needs to be moved to /etc/skel/.config/autostart/conky.desktop also the $HOME/.conkyrc needs to be moved to /etc/skel/.conkyrc
The installer might also like to add a bookmark or the companies website, so again the bookmark can be saved using the temporary account then the $HOME/.mozilla folder can be moved to /etc/skel/.mozilla.
Afterwards the computer is not turned on again until the person who the install is for turns it on.
When they do they will setup their user as shown below