Folding a fitted bamboo sheet or any fitted sheets can be tricky due to its elastic corners, but with a bit of practice, it becomes easier. Here’s a step-by-step guide:

Step 1: Hold the Sheet

1. Hold the sheet inside out by the two adjacent corners of one of the shorter sides.
2. Place one hand in each of these corners.

Step 2: Fold in Half

3. Bring your right hand to your left, folding the sheet in half, and tucking the right corner over the left corner.
4. Adjust the sheet so that the seam runs along your hand and the corners are snugly nested together.

Step 3: Fold the Other Corners

5. Reach down and pick up the corner that is hanging in front. Bring it up and tuck it into the two corners in your hand.
6. Do the same with the final corner, bringing it up and tucking it into the other corners.

Step 4: Lay the Sheet Down

7. Lay the sheet flat on a surface (like a bed or table), keeping the fitted corners together and the elastic edges facing up.

Step 5: Square Up the Sheet 

8. Straighten out the edges so the sheet forms a neat rectangle.

Step 6: Fold sheet into a Smaller Rectangle

9. Fold the edges in so all the elastic is hidden and you have a clean rectangle.
10. Fold the sheet in thirds lengthwise by bringing one side into the middle, then the other side over it.
11. Fold in thirds or halves crosswise, depending on the size of the sheet and your storage space.

Here’s a visual guide to help:

1. Corners together: Hold two corners inside out.
2. Tuck corners: Nest all four corners together.
3. Lay flat: Create a rectangle.
4. Fold: Tidy up and fold into a smaller rectangle.

With these steps, your fitted sheet bamboo sheet should be neatly folded and ready to store.