Try to wear as much black as possable for the ritual, nothing special. But do it at night since your entergies are different at night. Then prick or slice your left index finger and take a pen tip and sign your name with as much blood as possable, it dosent matter how much but as much as...

No dont worry most of them can be very forgiveing if its your first time, they understand, first time i contacted Marbas and FurFur (So she likes to be called) they were completely forgiveing and understanding about the situation. And of course the father is always forgiveing and understanding...