Project custom object records should only be seen by the owner of the record and users above the owner on the role hierarchy. However, for some Project records, the Training Coordinator must also have Read Only visibility to the Project record.

Create a custom picklist field on the Project object called “Priority” with the following values: High, Medium, and Low. Then create a criteria-based Sharing Rule for Project records where the Priority = High to share those records with the Training Coordinator role.