First, Peres catches the snowflakes on a tray lined with black velvet, so that they don’t melt immediately. Then, he takes them into his garage and uses a needle to transfer them onto the glass that goes under his microscope. He essentially is using the microscope like a lens attachment, with his camera attached at the top where you would normally look through.
The tricky part, however, is that he must do all of this and take all his photos in less than a minute. Then the snowflake melts, and since no two snowflakes are alike, there are no second chances.
You can see some of Peres’ snowflakes on Instagram.