When do you put in the "Bar's Leak" solution into my car?

I have a Honda Prelude 2000 and i don't have money to fix the seals in my car. My car leaks a little so i was thinking this will be a good temporary thing til I get some money. When do I put it in? After i remove my old oil sure but before i put my new oil in or with my new oil. Do i let it sit in the car with it on? or what do i do?