Hi Daniela,
Have you had an opportunity to review the following posts: Eloqua 10 Best Practices Template: Welcome Campaign and Gain Your Hours Back Nurturing: Welcome Campaign? I think this would be an awesome starting point. It offers a ‘Homework’ section of helpful things to think about & configuration steps to complete for a welcome or nurture campaign.
Gain Your Hours Back | Nurturing: Welcome Campaign
When you are ready to create the campaign you can leverage the two templates saved in the Template Gallery > Eloqua Best Practices. They are saved as BP Welcome & BP Simple Nurture.
I hope this material helps you get started
Jaclyn