Step 1:
The other side of this paper is golden brown. I used transparent tape to make the red side extra shiny.
Prefold in half over these two lines.

Step 6:
Prefold, then turn the model.

Step 5:
The prefolded squares pattern is used as guidance for the folds in the next steps.
Fold the edges to the yellow lines (which lay in the middle of the prefolded lines).

Step 2:
Fold the edges to the centerline.

Step 4:
Repeat steps 2 and 3 in this direction.

Step 3:
Fold the edges to the centerline, then unfold the model.

Step 10:
Fold these two edges straight upwards again.

Step 8:
Press the edges downwards

Step 9:
Fold these two mountain-folds straight upwards.

Step 7:
Fold the 2 mountain-folds straight upwards

Step 16:
Press the corners flat between your fingers.

Step 15:
The red line shows the curved edge.
Repeat step 14 on the other three sides of the model.

Step 12:
Repeat step 11 with these two edges.

Step 11:
Hold the model flat on a table (see yellow dots) and fold both edges straight upwards.

Step 14:
Pull these two edges to the right and glue/tape them to the model.

Step 13:
Fold the four corners inwards, use tape or glue.

Step 18:
Press (some of) the corners flat between your fingers, see arrows as example.

Step 17:
This is the other side of the model.
Pull the edges outwards a little, see arrows as example.