You just pitched the studio or the network and they want to move forward. Congratulations, that’s a big deal!
But let’s be clear on what this means. They’re pay you to write the pilot script.
They’re not saying they’re going to put it on the air.
They’re not even saying they’re going to shoot it.
However, all parties will still have negotiate the terms of the agreement as if the project were going to the air. The studios want the details hammered out now, because this is when they have the most leverage on you.
Here's a list of deal points that you will be fighting for: