Step 1:
The other side of this paper is darker brown. Other color combinations are fine too (red and black, yellow and green, light green and dark green etc.).
Prefold over these two lines.

Step 6:
Use transparent tape or glue to make the model flat (tape makes the snake look more shiny).

Step 5:
Fold the lines into the right direction, start with the folds in the middle.

Step 2:
Fold the corners to the center

Step 4:
Fold the edges to the centerline.
Then unfold the model.

Step 3:
Fold the edges to the centerline.

Step 10:
Fold / press both corners inwards

Step 8:
Mountain-fold over these two lines.

Step 9:
Fold over these two lines.

Step 7:
Mountain-fold over these two lines.

Step 16:
Bend / fold / curve the body into various directions, see arrows as example.

Step 15:
Fold the model in half over the yellow line and the head downwards over the four brown lines.

Step 12:
Fold the tip upwards

Step 11:
Fold both edges outwards / upwards

Step 14:
Press both teeth flat from aside

Step 13:
Fold over these four lines.

Step 17:
Pull the edges outwards again.