Types of Milestone Constraints:
Start Milestone - No constraint but start date must be set here before project can be scheduled
Interim Milestone - You can add as many as you like, and this is to track important Interim deadlines.
Constraints available on Interim Milestone:
Start On
Finish On
Start On or After
Finish On or Before
Finish Milestone - You can add one of these to the project.
Constraints available on Finish Milestone:
Finish On
Finish On or Before
Types of Activity Constraints:
Constraints available on Activities and Tasks:
Start On
As Late as Possible