WTF is Cognizance & Taking of Cognizance???

Yaar samajh nahi aaya! In CrPC, 2 concepts: Cognizance & Taking of Cognizance. Sab kuch clear hai except ye dono. Cognizance is when magistrate frames charges, right? Lekin phir kya hai Taking of Cognizance? Ismein kuch extra steps ho jaate hain? Magistrate ko kya karna hai aur pehle kya karna hai? BNSS mein bhi ye concept aata hai, par wahan bhi samajh nahi aayi. Koi bata sakta hai ki ye do cheezein kya difference karte hain? Inki boundary kahan se kahan hoti hai? Please help! Entrance exam mein bhi ye question aa sakta hai, par mujhe thoda clarify karna hai.