You will need to look here and find your own device. Look for the "bootable CD" download, which will give you an ISO file.

Then you need a Perl script from the internet (geteltorito.pl, I attached it too, because, you know. Internet.) to extract the El Torito boot image from the Lenovo-supplied ISO.

Pro-Tip: Don't click on the cdpage.com link from the script.

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cd ~/bin
wget http://userpages.uni-koblenz.de/~krienke/ftp/noarch/geteltorito
chmod u+x geteltorito

Assuming the ISO file was downloaded into ~/Downloads:

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cd ~/Downloads
geteltorito -o bios.img your_iso_file.iso

Now insert an USB-Stick you can comfortably use dd with. Assuming this gets the name /dev/sdd:

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sudo dd if=bios.img of=/dev/sdd bs=1M

Now you should reboot, press Enter and then F12 and boot from the newly created USB-Stick.
It may be required, that you change the BIOS/UEFI-Order-Settings before you can boot from it.

Once you booted just follow the instructions. When you think it should do something, but does not do anything, instead of powering off or removing the USB-Drive try hitting Enter or Escape.