From GEAR Software Knowledgebase
If the append mode is set to AutoAppend, GEAR automatically selects the last session/track on the CD to append the new data to. In order to be able to select the appropriate session/track yourself, you must set the append mode in the GEAR Options/Preferences/Append to Manual Append.
To select a session/track:
1. Insert a multi-session capable disc in the recorder.
2. Select "Add new session to CD" in the GEAR project panel.
3. Set the Append mode to manual under the Append Tab in Options/Preferences.
4. Click on the Append button in the GEAR project panel.
5. Select the track/session to append to. If you delete any of the original files, the data will become inaccessible once the new track/session has been completed.
6. In the explorer view drag the files to the volume window.
7. You can now start Testing and Writing.