I agree it was difficult at the beggining to get the pointer working. But know I can copy paste with no problem.

As the thread you pointed say, you have to put your finger/stylus in the left lower corner (Outside the screen) and bring it in (Without lifting it). You should see the arrow icon below your finger.
Position the icon at the beggining of the text you want to copy, press the shift key and drag the pointer until the end of the text (Never lift your finger until you finish selecting). Then press Ctrl+C and you're done!

You can also lock the mode as it is seen in the video, pressing the arrow icon in the lower left corner.

Cheers