Admissibility of Hearsay vs Secondary Evidence

Dekho, I am confused between hearsay and secondary evidence. Kisi ko batao ki dono mein kya fark hai exactly? Hearsay hai toh jo witness ke statement ka use direct evidence ke jagah hota hai, phir secondary evidence kya hai? Abhi tak toh mujhe lagta hai ki secondary evidence ke cases mein bhi hearsay ka application ho sakta hai. Koi explain kare kaise in dono ko alag alag consider kiya jata hai, especially in Evidence Act. Mera mind lagta hai confused...