How to make a envelope

Hi I'm going to use my Chinese Homework paper as I do not want to waste my A4 size paper.So let get started !

Lol I was being Random and Crazy

Fold it in half

Then open it

You can see the line and then fold it like a triangle

Do the same for the other side

Fold the small side into small triangle

Do the same for the other side

Then fold upward into staircase-like

Do the same for the other side

Then fold it into 135 angle

Do the same for the other side

The open space that I was pointing ,it is okay like this because it a design and for the card you are putting in it is 7.5cm Wide and 11.5cm Long and for the A4 size paper is 9cm Wide and 12.5cm Long.

The music in the background : I Should've Kissed You by One Direction Thank you for seeing this!