page is for those who want the instructions to learn how to apply a gate-fold.
Gate-fold is two valley-folds applied to a square paper. The name "Gate" is used for this folding technique since its action is similar to closing a gate.
There are two different gate-folds: one is horizontal gate-fold and the other one is vertical gate-fold. They are actually the same technique since the difference is only 90° rotation between two.
This is an animated instruction so it would be very easy to follow through. You are not required to have any prior knowledge about origami.