Yes I know I said easy ... at least it is in practice but it is a little hard to explain so hopefully the pictures will do most of the talking for me!
First off you will need a sheet of paper, a ruler and a pen (either a ballpoint or sharp pencil)
I used a 6x6" inch paper here. It will create a 2.1"x 2.1" box.
1. There are different techniques for this box. All of them seemed to result in an unsightly cross on the base which I didn't like at all so this is my version. You will first need to lightly draw a line diagonally from corner to corner like the image above.
2. Now fold one corner up so that the point is touching the cross you just drew.
3. Repeat last step with the remaining 3 corners until you have a piece that looks like the above image.
4. Now fold the left side of your piece into the centre and then the right side. Both sides should meet in the middle. ( you will need to make sure the paper underneath doesn't travel as you fold. the points need to remain in the centre.)
5. Now open up the folds you just made as well as the points on the left and right side so you are left with this. Now at this point you can stick down the top and bottom points before you move on.
6. Now you need to fold the bottom edge up. Conveniently there is a line (which you drew in step 1) to line the edges up to. Now repeat with the top edge.
7. open the last folds you made. you will need to score or in this case I drew using a biro along the bottom right part of the triangle. Just like the above image. Repeat on all four bottom parts of the triangles. This will make folding easier.
8. You will need to fold the lines you just scored in such a way that you recreate the image above (hard to explain I'm afraid, much easier to show.)
9. you are aiming to fold the right point over so that it sits inside the box. Once in place you can glue or tape there if you wish.
10. repeat on other side.
Now you should have a box. If you wish to make a box with lid then you need to cut a piece of paper half an inch wider each way. In this case I made a smaller one to fit inside. It was 5.5" square.
Then all that is left is to decorate!!
Other ideas are to keep making progressively smaller boxes like Russian dolls! I started with 8x8" paper and kept going until I used 2x2" paper! (got very fiddly!)
We will need this box for future tutorials so thought it would be good to do early on!