In this article you can find information how to add a custom field - formula type.
First step is creation of new custom field on Project object. Go to Setup > Create > Objects. On the list find "Project" and then in Custom fields & Relationship section click on new button:
As a Type choose "Formula" and click next. Now as you can see below you can choose the formula return type, as an example for this document we choose "Text". Insert Field Label and Field Name and then click next.
Enter the formula which you want to be displayed on that formula field and click on save button:
When your custom formula field is already created on the Project object, go to Admin page to make it visible on Project Detail Page. On the Custom Properties tab from the drop down list choose project and click on Add button:
Fill in all data and click the Add button:
Custom field formula type has been created. You can find it on Project Details Page in Project Details section: