As we are a big family I would like to ad my grandfader, grandfaders fader, his brother and sisters, their children etc. Then it would be clear to all how we, now living, are related to each other.

Yep, just go ahead ;-)

There are some help videos which should make it a lot clearer:
http://kindo.com/help/en/

Otherwise, just drop us a mail, or ask us here and we'll get back to you asap ;-)

/gareth