You want to choose one way or the other. Either doing it manually or using auto-compute. It may depend on how many activities you are looking to update. There is information on updating in the use guide as well.
Common updating process steps:
Create a baseline
• Identify the new data date
• Enter activity progress throughout the week (update duration remaining & at complete, dates,
or physical % complete).
• Report resource use and costs to date (done automatically by timesheets & apply actuals).
• Reschedule using the new data date (done by job services).
• Perform baseline analysis.
– Compare current plan to baseline plan to analyze variances.
• Monitor project progress with reports.
– Determine whether project objectives are being met.
Updating the Progress of Activities Using P6
Update status to define percent complete and start and finish dates.
To update status:
1) Click Projects.
2) On the Projects navigation bar, click Activities.
3) On the Activities page, select an activity and click the General detail window.
4) In the General detail window, in the Status section:
a. Select or clear the Started and Finished options.
b. If you select an option, click
and select a date from the calendar.
c. Enter a percentage in the Activity % Complete field.
5) On the Activities page, click the Actions
menu and select