This action can be done both in "Contacts-Segmentation" and in "Campaigns > My Campaigns"
CREATE A CONTACT LIST
If the segmentation feature is not applicable to your specific case you can upload a static contact list (e.g. you want to send to a cross project audience).
This action can be done both in "Contacts-Segmentation" and in "Campaigns-My Campaigns
Step 1 - Name your list
Step 2 - Import your contacts
Recommended if your list contains only email addresses
Recommended if your list contains several fields (first name, last name, country, etc...)
You will have to match the properties that you want to keep for your contactst.