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Now that your project is being down-sampled to boring old High Definition...
Open your sequence in the Timeline window and select the video and audio tracks to export. Mark an in point at the beginning of the portion of the timeline to export and an out point at the end of the portion of the timeline to export. If the whole timeline is to be exported mark an in point at the beginning and an out at the end.
Here is an example of how your timeline should look before exporting.
Next go to >File>Output>Export to File>
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