duplex algorithm for data splitting

#1
Hello,
I have problem understand the last step of duplex algorithm.
After I have found my othonormal maxtrix, I have found a pair of point that is farthest away from each other and put in estimation data set. Then remove this pair. Then, take the next pair with farthest away from each other and put in prediction group.

After I have two points in estimation and two points in prediction,
I do not know how to place the rest of points.

Please help me.

Thank you very much