Hi kilo,
first a warm welcome on our forum. Your first look should be at the wiki:
https://librepilot.atlassian.net/wiki/I am not sure about your experience with quad: do you have experience in flying quads or other aerial models? If yes, going into PID tuning may a good idea. If not, I'd suggest to chose a working template from Tools->import template and stick to attitude for a start until you feel comfortable. Otherwise flying it can be a frustrating experience.
If you are already well comfortable with your quad in most flight situations, you may want to dive deep into PID tuning. First step is to learn how a control loop works (P, I and D value), and how the different parameter affect the copter's behavior. This is essential, as manually tuning PIDs is not easy or trivial. Then you should take a good look at the wiki here:
https://librepilot.atlassian.net/wiki/display/LPDOC/Advanced+tuningI am myself are currently in that process with my two quads, and the more I learn about PID tuning the more I see, that doing it actually nearly perfectly needs a lot experience and try-and-error.