Your project shall be handled by project head. His/Her name & contact details shall be given in "Welcome mail" . Project head is responsible for project delivery and he will be in regular touch with you for any requirement or approvals. You can call or mail him for "knowing the status" or "requesting changes" or "other project related discussion". 

Other team members name shall also be mentioned in Welcome mail & they may approach you in the absence or unavailability of project head directly to ensure timely delivery. 

Content Writer:  Apart from Project head, if you have content writing in scope then you need to have separate discussion with "content writer" . Project head shall only responsible for project execution till delivery except payment & script/content part. The details of " Content writer" shall also be given in "Welcome mail" .