Paella is actually less difficult than it appears.
Philosophically speaking, this was a dish that was designed to get as much flavor into the rice (which is the bulk of the dish) as possible. Everything contributes to this - your meat choices, the veggies, the broth, the spices, all of it. We Americans haven't quite figured out that rice is much tastier cooked in something other than plain water.
First thing I recommend is that you go for something closer to the traditional Valencian paella (no seafood, just chicken and rabbit) to simplify, because many people ruin their paella by overcooking the seafood on the first try. I actually prefer to use just chicken thighs, not whole chicken, because the thigh is the most flavorful part, and by using just one part of the bird, I can be confident that it will all reach the same level of doneness, instead of some parts being grossly overcooked while others are barely done.
The most challenging part of the dish is the socarrat - the lightly toasted (not burned) rice on the bottom. Get this right, and you've mastered the art.
The trick is, getting enough liquid (usually chicken broth) into the uncovered pan so all the rice will actually cook to done over the course of the 40 minutes or so you'll be stewing it, and then the rice just starts to go dry a few minutes before you remove it from the heat - this is where the toasting happens, and where you'll have to watch it like a hawk.
I actually have a YT show up where I did it with chicken, chorizo, and shrimp (because I couldn't get any fresh rabbit)
As to your question about the saffron - you're going to know immediately when there's enough in there. The whole dish will start to take on a yellow hue. Add the saffron right after you add your broth, it will diffuse into the dish much easier with liquid in the pan.
One more thing I would recommend to a first-timer - get a short grain rice. I used Basmati on the show - and I would NOT recommend that to a beginner - it's much tougher to get long-grain done properly the first time out.
One more thing - you definitely need a large, shallow pan for this exercise. If you want to order a paella pan, PaellaPans.com
is a great place to get them cheap.
I'm not much for single-use kitchenware, though, so I prefer a 15" (or larger) cast iron pan. I got 4 solid servings and a bit of leftover out of a 15".
Hope this helps!