Rectangle Platform Popup Cards

This a tutorial for a platform popup card with a rectangular base. I did not use any special dies to make the base card. I show a few finished cards as well. I did not invent this style of card. I saw it on RUclips but I could not find the original. Besides, I wanted different sizes so I made myself some templates for 3 sizes. This tutorial is the A7 (5 x 7 inch) size.