Log time spent on an update (while posting the update)
To log time spent on an update, you must enable Task & Update Timesheets on the project
To log time spent on an update while posting the update, you must use the Complete Survey page to create the story. To log time spent on an update AFTER having posted the update, use the Time Spent popup.
Steps
Go to the Complete A Survey page
An additional box appears at the bottom of the page called How long did you spend on this?
Enter the time spent in Hours and Minutes
Press Publish Now