Account and Event Administrators can set times for each submission - abstract or symposium -  within a session when you create/edit a session.

In edit mode, click the 'Schedule individually' checkbox in the 'Submissions' area of the create/edit Session screen.

Choose the time increment (1, 5 or 15), enter the ID number of each submission/ symposium you wish to include in the timeframe within the session then enter the relevant start and end times.  You can schedule individual or multiple submissions in each timeframe.  Click 'Add New Time' to add each new timeframe into the session.

Click 'Save' when you have finished adding all the individual sessions.

When you preview/publish the program, the individual times for each submission are displayed when you click on the relevant session.