Step 6:
Valley-fold over these two lines.

Step 5:
Mountain-fold the corner on the right to the spot indicated by the arrow on the left.
Turn the model.

Step 2:
Prefold in half over this line.

Step 4:
Fold in half, then turn the model

Step 3:
Valley-fold over this line.

Step 10:
Valley-fold over this line.

Step 8:
Prefold the model in half.
Mountain-fold the corner on the left to the spot indicated by the upper arrow, it's a little above the centerline.

Step 9:
Valley-fold over these two lines.

Step 7:
Pull the flap to the right.

Step 1:
This is an a4 size paper with wood texture, I taped tin foil to the other side of it.
Black paper and tin foil is also great for folding the gun.

Step 16:
Press these two spots flat.

Step 15:
Valley-fold over these two lines. The corners indicated by the arrows are pulled upwards while you do this.

Step 12:
Mountain-fold over this line, make the same fold (=valley-fold) on the other side of the trigger.

Step 11:
Pull the tip upwards by making an inside reverse fold over the three black lines.
Fold the model in half while you do this.

Step 14:
I opened the model a little here.
Fold over these two lines.

Step 13:
Pull the tip to the left by making an inside reverse fold over the short black lines.

Step 21:
Press the edge inwards, do the same on the other side of the model.

Step 19:
This is a view from above. Fold the part between the black lines downwards, the folding lines are prefolded in step 18

Step 20:
Press/push these two corners to the left and against each other.

Step 18:
Press the edge inwards by making an inside reverse fold over the three black lines. Then open the model a little.

Step 17:
Fold the model in half again.

Step 22:
Mountain-fold over these two black lines, do the same on the other side.

Step 24:
Mountain-fold over this line, do the same on the other side (=valley-fold).
Push the trigger upwards a little (if necessary), see arrow

Step 23:
Mountain-fold over the upper layer, valley-fold over the layer below.