Hi! I am trying to burn and boot an installation disc (DVD) with Ubuntu Budgie.
I cannot get it to boot? I rightclick the ubuntubudgie.iso image and use brasero
to burn the image to a DVD but I cannot get it to boot 
What may I be doing wrong?
the definitive answer: https://help.ubuntu.com/community/BurningIsoHowto
although to be fair, I burnt many a DVD with no success because I did not read the instructions carefully. Caveat: Read twice, burn once.
Also: I had the devil of a time booting my 2006 mac pro 1,1 with an Ubuntu Budgie 18.04. Turns out the mac pro 1,1 had a 64-bit CPU, but a 32-bit UEFI! WTH? If you are in the same boat, you might look at using the .iso images modified/provided by Matt Gadient https://mattgadient.com/linux-dvd-images-and-how-to-for-32-bit-efi-macs-late-2006-models/
Good luck! I used up my co-workers stash of ancient/discarded DVDs burning installers, looking for the perfect linux build for my system.
Oh! Have you confirmed your DVD Optical reader is working? Just a thought before you burn multiple DVDs. You are hoping that your old tech is still functional, I bet.
Use Rufus (Google it) and a USB stick.
Also with such little information it’s difficult to give useful advice.
zilexa is right, sigska. Is there a reason you are using a DVD to install the .iso and not a USB? Once you burn the DVD, it’s used up, regardless of whether you burned it correctly or not. If you install with a USB installer, you can remake it as many times as possible until you get it working.