How can i Stack Gui items in Rows, like in the default backpack?[Solved]

O'k am working on a Gui, that has little Boxes that will have images in them, i want to be able to put a whole bunch of items into a folder and then have a script count how many Objects are in that folder, then Create rows of the Boxes with values inside of them in rows within the frame of course, I AM not script requesting i know how to do most of the script by my question is what kind of math should i use to make the gui move the boxes in rows.