Kya Evidence Act ko sections ke liye badla ja sakta hai yeh?

Main Evidence Act ki sections ko poori tarah se samajh nahin pa raha hoon. Meri teacher bhi bolte hain ki ab BSA (Bombay School of Advocacy) aaya hai, aur woh bhi sections ko badal dete hain. Lekin main dono ko same mehsoos karti hoon. Kya yeh dono hi bhai bahen hain ya koi aur cheez hai jo main samajh nahin pa raha hoon? Main kuchh examples dekh rahi hoon - section 3 of Evidence Act, woh kya karta hai? Aur BSA walo ne kya kiya hai? Kya yeh dono hi ek hi cheez hain? Please, koi help kare... Maine bahut confuse hui hoon.