Presuming you actually want to run the 6th World, i.e. Shadowrun, but before the Awakening itself, I highly recommend getting a hold of the 6th World timeline so that you can keep track of when things kick off - magic, truly functional cybernetics, that sort of thing.
Because the appearance of magic and high tech - the cybernetic man/machine interface that is the original Matrix, with the first Crash Virus hot on its heels, forcing the swift evolution of that tech - has had such a major effect on the world and corporations, you are going to have to essentially do a complete rewrite on your world's history, from whatever point-of-alteration you're taking it. Just as an example, no Matrix means no Universal Matrix Standards conference, which essentially means that the matrix-heavy Japanacorps - MCT, Fuchi, and Renraku - are going to be radically different. No magic means no dragons, which means Saeder-Krupp is going to be absent. No both means that there's no Nanosecond Buyout of Ares, making Ares significantly changed, and also means that ORO never has either reason or methodology to evolve into Aztechnology. No magic means Yamatetsu never has Buttercup, which changes the guts of that corporation - and therefore Shiawase might reign as the undisputed top dog of the corporate world.
It really is a massive undertaking; good luck.