magic slider card revers

i have alr posted this to diy too, im posting it here too. hey guys, i have a school project for which i have to create one of those slider magic cards like this: 
Easy magic slider card | no stamps needed! on yt, except that instead of the inside being black and white and when it slides out being colorful i need it to be the opposite, so like colorfull when inside and black and white when it slides out, is there any existing video on how to make it or are there any tweaks or anything i can do to this video. thanks! btw if you need to ask me any questions, pls feel free to. i have also searched online for this type of thing but i cant find it anywhere cus most of it is just like this video. i am also an absolute beginner at this.