Yesterday I was lucky. I opened the chest from the daily quest and wow... I got 953 DEC. I am very happy. For a beginner like me, that's a lot. So, which card should I buy or borrow? I have to think about

Hi, I'm new to Splinterlands. I started playing Splinterlands on Android yesterday and bought a Summoner's Spellbook. I was confused at first, what is this menu. So, I just click one by one until I understand