To-dos can be assigned to staff members from the Schedule within a project. To assign a to-do to a staff member, follow the steps below:
- Navigate to the Schedule page (Project > Plan > Schedule), and from the menu on the left, select the button next to the Milestone. 
- Click on the to-do in the menu that opens on the right. 
- Scroll through the list to find the required staff member. 
- Click on the staff member responsible for the to-do. This will place the to-do in their queue. 
You will see the profile picture of the person in the to-do list.
These steps are outlined below:

