How to add bitcoins to Bitstamp??

Hi,

I would like to buy for 30€ on bitcoins on the site of Bitstamp. I tryed to do this by clicking on Donate=> sepa but i only need to give in my amount of money without my bank account i need to enter so how is then possible that i can transfer 30€ from my bank account to my account for receiving bitcoins when i can't put in my bank information? When i complete that donation i only see an adres of someone where i seem to transfer my money to?? Is it free to transfer my 30€ from my bank account to this account for bitcoins or do i need to donate to that address first? what seems strange for me. Can one of you guys explain it in detail to me? On the support they didn't answer for 3 days already..
I'm from Belgium and Bitstamp should be the best exchange company for me i saw.

Grtz,

Jochen