A variety of Timing Constraints are only available for Auto Scheduled tasks. All Manually Scheduled tasks are As Soon as Possible (ASAP)
The most important thing to remember is that Timing Constraints have a higher priority on schedule than do links. Unless of course, you turn off that particular scheduling rule in Project Options. (Project Options / Schedule / Scheduling Options for this project / Tasks will always honor their constraint dates)
There are 8 Timing Constraints that can be applied to detail tasks and milestones.
Flexible
As Soon As Possible (ASAP) - Pushed toward the project start date
As Late As Possible (ALAP) - Pushed toward the project finish date
Semi-Flexible
Start No Earlier Than (SNET) a date - The task be pushed out in time, but can not start earlier than a date you enter
Start No Later Than (SNLT) a date - The task can start earlier than scheduled, but can not start later than a date you enter
Finish No Earlier Than (FNET) a date - The task can finish later than scheduled, but can not finish earlier than a date you enter.
Finish No Later Than (FNLT) a date - The task can finish earlier than scheduled, but can not finish later than a date you enter.
Inflexible or Fixed
Must Start On (MSO) a date - The task must start on a date you enter
Must Finish On (MFO) a date - The task must finish on a date you enter
Three Timing Constraints are available for Summary Tasks:
As Soon As Possible
Start No Earlier Than a date
Finish No Later Than a date
