Kami means "we" excluding the listener. Kita means "we" including the listener.
Kami datang dari Indonesia. We come from Indonesia.
If I say like that to you it means I and my friends come from Indonesia but you are not (excluding the listener)
Kita pasti bisa. We can do it.
If I say it to you in the middle of tournament for example, it means I, you, and all of our member can do it (including the listener)
Kami and kita are different but many people think kami and kita are same then used "kita" to say "we". In daily conversation you can use kita for we but you must be careful if you are in formal situation like presentation, seminar, writing etc, you should know the difference between kami and kita :)