How to fill the 325i Auto Trans

[2001 325i]

I am a new member to this forum due to the great advices I've read thus far. I need some help...

I've done everything to change the transmission oil in my 2001 325i; except now I am unable to fill the transmission...when I pump the oil, it comes right out from the fill hole...I am also unable to stick the hose from the pump deeper than half inch.

Does the car need to be on and the trasmission in the park position? Does the transmission need to be hot in order to receive the new oil?

Thanks in advance,

2001 325i