First, you need a rectangle of paper. You might need to cut or fold the paper in half so that the ratio of the breadth to the length is 1:7 ( the length can be longer, it doesn't matter)

Step 1:

Next, fold down one corner of the paper. Unfold and repeat on the opposite side. Create a '' waterbomb base'' . ( See picture

Step 2:

Repeat on the opposite end. Now, take one of the folded ends and fold the two flaps to the middle ( see picture)

Step 3:

Fold in the two rectangular edges on the left and right ( see picture) i'm bad at explaining things.

Step 4:

Nearly done! Now fold the whole thing in half, so that the folded waterbomb base rests on top of the unfolded base. Tuck both the tabs of the folded base into the '' pockets'' of the unfolded base.