I want everything in my selection box to be put into a table, how?

So I made a selection box script so I can make a box such as you do in studio when you drag your mouse. So on my screen I can make the box bigger, smaller, whatever. Now, I want to select everything inside of it such as you do in studio. All I need for this is to get a table of everything inside of the frame. I don't know how to do it though. Just need help getting the table.