To add a confirmation click on a green pin that already exists. Enter the text as it appears on the map and click the "Done" button.
If the text you typed matches exactly the existing text the pin will change colour to purple for everyone.
If the text you typed does not exactly match the existing text the pin will turn brown for you, but will remain green for everyone else. When a third transcriber enters text which matches the text that either you or the original transcriber entered the pin will then turn purple for everyone.
Please note: If you are confirming an existing pin the colour of the pin icon within the transcription box is green. If your cursor moves off the existing pin and is going to create a new pin the icon will become brown.