Over high heat, bring the shrimp to a boil in one pot until the shrimp turn pink.
In a second pot, bring the mussels to a boil until the mussels open.
Dice the onions and bell peppers.
Cut the squid and chicken into large pieces.
Remove the shrimp from the boiling water and peel.
Add the shrimp water to the paella pan and season the broth with a little salt, pepper and saffron.
Add the rice to the paella pan and simmer.
In a second pan, sauté the squid and chicken briefly.
Add onions and peppers to the rice once most of the broth has cooked off.
Lastly, add the sautéed chicken, sautéed squid, shrimp and mussels to the paella pan and let the remaining broth boil away.
Cut the lemon into quarters and decorate on the pan and then serve the finished paella in the pan.