View the worklog report
Depending on granted permissions, a user can view her/his own or other users' Timesheets on the Customer Portal.
Login to your Customer Portal.
Click on Worklog report button at the top right corner of the page.
Select My requests or All requests to view the relevant Timesheet.
Define a needed time range.
Log work on the issue
Login to your Customer Portal.
Navigate to the desired issue.
On the right-side panel click the Worklogs button → Log Work.
Fill the Date, Amount of time spent and Description of work (optional) fields.
Confirm by clicking LOG TIME.