Associate contact to an Opportunity

1. Go into the respective opportunity.
2. Scroll down. On the left panel, click Associate Contact. Picture below for refernce.
   
3. Select the contact from the address book which you would like to associate to the project.
   
4. Select what role they are playing in the project > Click ADD
   
   
   OR
   If you can't find the contact in your address book, Click on CREATE NEW CONTACT. 
   
5. Fill in the details of the contact & Company.
6. Select the role they are playing in this project & Click ADD.