Open a job and swipe the menu out from the right-hand side of the screen. Select 'Time Items'.
This will take you to a screen which shows all the time items currently linked to your job.
To add a new time item to the job, click on the plus icon and navigate through the form, specifying your desired times.
Then click the 'save' at the top of the screen to attach this time item to the job.
To modify or delete a time item tap and hold it in the list and choose an option from the menu which will pop up.