I want to burn Ubuntu boot disk on a DVD along with some documents I need. This way I can launch Ubuntu on someone else's computer in case I need to work. This would allow me to have important notes and commands I use frequently on some text files on the disk.
That would be much better using a LiveUSB instead (Install Ubuntu on USB drive). You can apply persistence to it, which will permanently save your documents on the USB drive, until you delete them! USB is also a LOT faster than CD.
Try and install Ubuntu on your drive from "USB creator", installed on Ubuntu. Persistence does not work on every computer, however. Although you could still use a Live-USB installation (Files resetted at logoff), and store your files on the same USB drive. Ubuntu only reset specific folders where it is installed on the drive. You can still use the drive for storing stuff, even if you have Ubuntu installed on it.