Need some expert advice

[Deleted User]

Well, here goes:

I've been running for about a year now and have only ever entered into a 5k which was more of a fun run, however this year I decided that it was about time to enter something proper, so I've signed up for the Great South Run (10 miles).......I've downloaded some training programs from various sites but these haven't really helped as its too full of jargon like 5k/10k race pace!!!. How do I know what my pace should be? Does it really matter? Is there anyone out there that could help?