It's been a while since I played the demo, but from what I remember, you get down from the tower and you get south according to the map. You meet Ucogi, then you go right (west), then north (through the labs at the top right corner on the map). The Beta ends when you get to find Alice.
The map should have red circles that tells you where to go next, but these objectives may change from time to time, according to the story. The new key card that you get from the tower is used on a couple of doors, until you meet Ucogi. It's not about the card color but about what level doors it can open. I think it opens doors lv2.