Technologies represent various scientific bodies of knowledge. You discover them by spending Research Points, produced in your Research Labs.
Technologies give you access to more advanced facilities or units. For example, Human Cloning gives you access to the Barracks facility.
Technologies have other technologies as prerequisites, which you must master first. The technology tree shows the relation between all available technologies. Some technologies cannot be researched directly, but are awarded when you complete specific missions.
2. Conducting Research
To be able to do any research you need to first build a Research Lab in your colony.
A Research Lab will produce Research Points automatically over time. There can be only one Research Lab in each colony but the Research Points add up together from all your Labs.
Once you have some Research Points to spend, click on the Research area to see the Technology Tree. Some technologies may be available while others are locked. Click on any available tech to see their detailed information and get a chance to complete them.
Research Points are not only used to discover technologies but also to complete various other tasks in the game.