[ubuntu] Help installing Ubuntu on MBP from DVD-R?

Hello Linux people!

I would like to discover the joys of Linux, but I'm having a hard time installing :(

This has been my procedure:

1. Partitioned my laptop's hard drive to set aside a partition of 30 GB for Ubuntu.
2. Downloaded Ubuntu Desktop ( "ubuntu-12.10-desktop-i386.iso") and burned it onto a DVD-R.
3. Installed rEFIt to be able to dual-boot OSX or Linux when my computer boots up.
4. Inserted the DVD and restarted my computer.
5. When it booted up again, I chose the Linux Disk instead of OSX.

And I got a black screen with a blinking cursor. I assumed the computer was just taking time to process things, so I waited for about an hour until restarting my computer and giving up.

Did I do something wrong? Am I missing some steps?

I'm running a mid-2012 Macbook Pro, OSX 10.7.5 Lion.

Any information would be greatly appreciated. I'm sorry in advance for any cross postings.

Thank you for your time,
Sebastian