Each concept should include:
- A name and physical description: "who is your character?"
- A description of background and activities: "where is your character?"
- A description of general desires: "where is your character going?"
- A description of abilities and possessions: "what is your character?"
While not required, it might be useful to make use of this character creation worksheet that I like from Black Shield Gaming:
It also might be a good idea to keep Burning Void's guide to character concepts in mind - not that I'm opposed to people using stereotyped characters, but you should at least do it on purpose.
For those who remember anything about their Shadowrun characters, you may feel free to use them (assuming you can remember enough to fill in character concepts appropriately).