Hello Waitiaki ! Thanks for your reply....Now, my situation has advanced.
Now, I know how to connect the power supply.
However i think I have a problem with a short circuit somewhere on my board as well. I am new to this technology and am not quite sure what went wrong. I was trying to connect my power supply to the sanguinololu, but it wouldn't work. I ve tested the power supply, it works fine, which means there must be something wrong somewhere on the board. Do you have an idea about how to find out? Is it possible to fix or do I have to buy a new one?