Hi Nastja, 

In rouns 1, you join the ch 30 with a slst to form a circle (make sure the chain isn't twisted when joining), you then ch 2 and start working in the same ch where you made the joining slst, and then you make 30 hdc in the ch, working all around. All of this still counts as round 1. You then continue working round 2 in the hdc you made in round 1. I hope this helps you out, enjoy crocheting!