Select "import" from the Titles Menu of the Video Subtitler and paste the data you just copied into the "import" box (dont forget to click "import"
When you finish a session, select Export from the Titles Menu then take the Timed Text option. Select the data that appears in the box and "Copy" it. Click the "Manage Data Filee" Link to return to the editor page and select the .xml file you started with and replace the odl data wit the new data you jsut exported and click "Update" on the editir to save it until the next tiem you visit to do soem more subtitlign work.
That's it -- you're good to go! There is a Help menu available to get you started with the job of subtitling