Time Complexity

Time complexity mein mujhe ye smjh nahi aaya ki constant time kaise hota time complexity mujhe iska concept smjh nahi aaya jaise ki monu bhaiya ne btaya ki ham compare karte hai dusre program se time complexity mein to aisa to kuch hai nahi jab time complexity nikalte hai to . isko detail mein btaye kya mujhe answer phone call ya phir video solution mil skta hai?