The very first shadowrun mission is actually a pretty good introductory scenario -- let's characters get to know each other, let's you give them one or more free fixer contacts, and requires more 'using the rules' to do basic tasks than it does combat. The only thing is that it is written for third edition not fifth edition, so you are probably best to come up with all of your own stats than try to translate (third edition rules were very different, with different attributes, dice system, etc)
(Shadowrun missions are a series of mini-campaigns designed to be a sort of common campaign -- seasons one and two are free on the catalyst site)