I make paella (more often bastardized versions for the true purists) often - I just made it this weekend for my mother’s 75 birthday party.
There are so many recipes out there - what exactly are you looking for? Are you looking to do it in an oven (versus over a burner or grill/coals/wood)? Are those the only things you want to add (mussels, crab, shrimp)?
My general recipe:
brown meats/sausage in paella pan, remove - preheat oven to 500
add finely chopped onion and red pepper and saute until cooked down but not browned (I don’t add more garlic if the sausage I’m using is garlicy)
add rice (and some oil if needed) to onion/peppers and saute until rice becomes partially opaque but at least coated with oil
bring stock to boil in separate pot (sometimes I add saffron to the stock but most often I add it to the rice mixture)
add a cup of stock to the paella pan and use to deglaze anything sticking to pan
spread out rice and tuck in meats (if using) - add a few cups of stock and bring to boil
tuck in seafood and add stock to be at least 2x the amount of rice (e.g. 2 cups of rice 4 cups of stock - you may need more depending on evaporation/etc)
bring back to boil and put in hot oven for 20 min (if I’m using squid I usually add that after 10 minutes of cooking because it cooks quickly)
with 5 minutes left, toss frozen peas on top
remove from oven and cover with towel - let sit 5-10 minutes
That’s it in general. Sometimes I think the mussels get too overcooked - so I have at times added them 1/2 way through oven time - but if I’m using clams then I like adding them where I did above. If you were using canned or cooked crab I would add that towards the end too.
This method doesn’t always create a cook bottom crust if you’re into that - but I have only had success with that doing it outside over a fire . . .