I suppose the images will sum up everything, but I have added instructions as well.
Note: The word tissue that I use can be interchangeable with Kleenex/Napkins in some places. I prefer the word tissues.
P.S. I am entering this for the paper craft contest so vote for my tissue box if you like it!
Step 1: Materials
1. A nice(preferably sturdy) sheet of paper.
Using square paper would be favoured, but A4 sheets are fine as well. If you are using A4 paper, the next step is for you.
Let us not digress.
Step 2: Converting an A4 Sheet Into a Square One
Fold your paper diagonally, making a triangle.
Now, take the rectangular portion NOT covered by the triangle and tear it off or cut it off with scissors. The resulting sheet of paper must be square.
Step 3: The Basic Folds
First create two diagonal folds, making two triangles and revert the folds, making it a square again.
Then make a top to bottom fold. Unfold and fold the paper from left to right. When you unfold the paper, you will have as asterix.
Now, take the top edge and fold it towards the centre of the square. Do the same with the bottom edge. Move to the heart of the procedure with the final figure.
Step 4: Heart of the Origami
Take the top edge, and fold it towards the centre. Do the same with the bottom edge.
Now, unfold. If you like, you could make the creases deeper and flatten the paper.
Okay. Take third crease from the top and fold the top edge downwards into a triangle.
The triangle will have two creases, I have marked the approximate place from which you must take the next fold. Done?
Now make two folds upwards on the same shape. You will have a small triangle protruding out.
Do the same for the other side.
Phew! Now just the finishing up, the revelation if the origami.
Step 5: Finishing Up
Decorate the tissue box if you want to, and go to the next step to find out how you should store tissues in there.
Step 6: The Tissues
To insert the tissues, open the flap, insert the tissues as per given in the pictures and close the flap.Under the last flap of each tissue, insert the first flap of the next one.
This maintains the flow of the tissues.
That would be about it. Thanks a lot for reading and please do vote if you liked my Instructable.