At the end of the tutorial, you need to enter a referral code to gain 100.000 rupies (ingame currency) and a rare card.
Use this referral code: hkm22901
Tip: in the beginning, use the maximum amount of cards possible (8) to evolve your cards. For example, when you have card A, you two cards to evolve to A+. To this two times, then use two A+ cards to evolve to A++. Again, do this two times, then use two A++ cards to evolve to the final form. This will give you a head start.