How do you put apps into folders?

Hi everyone. I am wanting to create folders on my iPhone to better organize my apps. My problem though is that I can't figure out how to put apps that are on different pages in the same folder. For example, seven little words is on my third page and word warp is on my fifth. I want those in the same folder, but can't figure out how to do it!!!! Any help with this would be greatly appreciated. :)