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The easiest way to burn files onto a DVD is just open Finder, select all the files you want to burn with Command key, right-click them and choose "Burn".
Then, if you want to burn a ISO or DMG file, you may have to use Disk Utility instead of burning them with Finder, if you want to show its content instead of the file
If there is no iDVD on Your Mac (and it's not on newer Macs as Apple discarded it) then You need a program that can do this.
Your Mac can burn CDs and DVDs - BUT DVD as Data-DVDs not as Video-DVDs - they need a program to be encoded and STRUCTURED as such.
• iDVD is part of the boxed version of iLife'11 and can only be bought outside Apple as on Amazon and e-bay
• DVD Studio pro - Part of FinalCut Studio Pro bundle - this to has expired and can only be bought second handed. (High price and tough learning Curve - but best ever done.)
• Roxio Toast™ - Not as elegant as iDVD - but has many other positive additions (I like it as 10-Pro incl BD-component) (now version 11)
• Burn - only free alternative I know of on internet. Very simple - Just for doing a plain Video-DVD
only You can buy from Apple is
• FinalCut Pro-X which also can burn to DVD but without any nice themes.
You can also buy Compressor from Apple for $50 US. It will also create DVD and BluRay but without the nice themes.
Yours Bengt W