door window

how is the door window meant to bee put into the drivers side door on a 1973 duster, broke that window last summer and found another one from a 74 duster but i cant get it to steer properly..
right now i have to have it rooled down all the time when driving and when i park the car i have to give the window a light push inwards to make it seal agianst the sealing:(
any ideas apreciated, hard to explain the problem but i will try better if you guys need it;)
thanks in advance