You don't really need an example. Your QVD will be a table of data which you can amend. It can be from SAP, excel spreadsheet etc but won't contain any charts etc.This would have a store statement at the end
STORE <table name> INTO (qvd);
You can then read this into a front end QVW (a full QlikView document) which would contain data from several sources, layout changes, charts, etc.
The advantage is that you can load the data in quicker if it has been converted into a .qvd
p.s. I did post a link on this thread but it is stuck in 'moderation'. Have a look at www.quickintelligence.co.uk/qlikview-optimised-qvd-loads.