Step 1:
Both sides of the paper have another color.
Prefold in half first, then fold the edges to the centerline.

Step 8:
Fold over these two lines.

Step 6:
Glue or tape the edges together (just the tip of the edges).

Step 11:
Turn the model.

Step 10:
Make the same folds as in step 9 on the other two edges

Step 9:
Fold over these two lines.

Step 5:
Fold the four corners inwards.

Step 7:
Fold the edge to the left

Step 3:
Fold over the purple line.

Step 2:
Fold the edges to the centerline and unfold the model.

Step 4:
Fold the prefolded lines into the right direction.

Step 12:
Press/fold flat, see pink arrows.

Step 13:
Fold the edges in half, do the same on the other side

Step 14:
Fold over these two lines.
Turn the model and make the folds of the final step.

This is a standard/normal Origami chair with pink seat

Done!
This is an Origami video tutorial for folding the office chair:

Dollhouse office