I got a few questions:

1. I know I get a science victory by building the gaia controller. this consists of 3 pieces. But how can I built the Obelisks? I can't find it in the city. Do I use units to build it?

2. How can I built tile improvements? Cities build these automatically but I wanna build roads and other improvements outside of the city range.

2. To build tile improvements just open the tile improvement menue and of course you need enough public works. You can build things like fortifications radar stations or listening posts outside of you borders. But the terrain tile must be in the view of one of your units. So far as I know you aren't able to build farms, roads et cettera outside of your border. And I think this is an balance design decission. In CTP1 you are able to build roads or better maglevs and undersea tunnels directly to an enemy just to accelerate conquering. Maybe there is a way to change it. But you can expand by building fortifications on a neutral terrain tile. Then your are able to build roads there.