this is easy - powerpoint has an alignment tool - as well as tools for equal distribution of objects.

It looks like you created a box, grouped it and copied it 16 times. First select all the boxes in the top row either by Pressing control and clicking on each or by highlighting all four.

Next go to picture tools/Format and click the "arrange option on the tool bar. Go down to Position Objects /align and a sub window opens with options on how to align them. Alighn them all by "top.

then, while they are still selected, do the same - Go down to Position Objects /align and a sub window opens - this time select "Distribute Horisontally".

Repeat for each row