While setting up a Stream you are able to quickly assign that Stream to one or many Timing Locations.
Click the dropdown in this section to select one or many Timing Locations that you wish to use the times collected in this Stream for. For Chip Systems you would want to always assign as a Main Stream. Backup Streams are only to be used for manual timing methods like Time Machines, Summit Timers, or just typing in bib numbers into a spreadsheet.
For instance you may have a single Stream that has both Start and Finish Times. In that case, select both the Start and the Finish Timing Locations in the Main Stream Assignment Dropdown.