Step 6: Building the jellyfish
You have to sew together : the head, the tentacles and the belly. Place the tentacles between the head layer and the belly. I found it rather unconvenient to pin all the tentacles, so I marked the desired location of the tentacles on the belly piece with a pin (there is a little space between every tentacle) and sewed one tentacle after another.
You have 4 or five layers to sew together : 1 for the head, possibly one for the ruff if you sewed it at the bottom of the head, 2 for the tentacle and 1 for the belly. Do not even think about doing it by hand.
Stick a tentacle between the head and the belly. Keep it in place with two pins forming a cross. Sew all that mess slowly and carefully. Stop when you have sewn 6 tentacles out of 8.
Fill the head with filling. Do not overfill, you still need to sew 2 tentacles easily.
Sew the 2 tentacles left. It will be hard, since you have to press a big plushie under the foot of your sewing machine. You will likely have to stop some times and re-sew a bit that you missed.
Your jellyfish is finished!