Contract Law - Wtf is a Privity of Contract?

Arre, 3 din aur exam ka, aur abhi bhi maine yeh Privity of Contract nahin samajh liya. Lagta hai jab tak maine yeh nhi samajha, tab tak mera exam complete nahin hoga. Abhi toh maine sirf formulas aur definitions yaad kiye hai, par yeh concept toh pata nahi kaise se connect karna hai. Ek contract ek party ke beech hota hai, toh agar wala party (promisor) agreement break karta hai, toh kya dusra party (promisee) uska benefit kaise le sakta hai? Abhi toh main sochta hoon kya kuchh specific rules hain jo Privity of Contract ke baare mein bataati hain?