where can i find info on buildings and units that came with the expansion? i did not play the game when it came out so i'm kind of a dark reign newbie. last game i chose shadowhand and couldn't figure out what the matrix does :/ ....

Good question. I was about to dig out my original RoTS CD as it was as there's at least one fan expansion + extras Activision included on it that's not available on GOG.com (yet). I can't recall if there was a jewel case inset for the expansion or not any more. As to what the units and buildings do well don't play the Shadowhand campaign until you've beaten the original as it's brutal by comparison and DR for it's time was rather complex with multiple armour types and weapon types that went beyond the RPS approach of a lot of RTS.

I assume you're referring to the Osiris Matrix there, so that is the Shadowhand's signature unit construction building essentially also being all that is required for the level 2 HQ upgrade.