I have noticed that many examples of internet which show creating the list definition have a GUID in the id of the field. How is this ID got? e.x.
Where is this GUID got from?
Usually in Visual Studio; Tools -> Generate GUID
While each generated GUID is not guaranteed to be unique, the total number of unique keys (2^128 or 3.4×10^38) is so large that the probability of the same number being generated twice is very small. For example, consider the observable universe, which contains about 5×10^22 stars; every star could then have 6.8×10^15 universally unique GUIDs.
For more information:
Go to the list settings page. Right click on "Title, description and navigation" and copy the URL. Paste that into notepad and copy everything after "List=" in the string. That's your URL Encoded GUID for the list. All you need to do is decode it here http://www.albionresearch.com/misc/urlencode.php