There will typically be one or two lead characters, even in ensemble productions. It’s Michael Bluth in Arrested Development.
It is Michael Scott in The Office. It’s a little bit murkier with Friends, but if you watch the pilot, Ross and Rachel get the most attention, and their will-they-won’t-they story is told right away.
Ross and Rachel are the show’s de facto protagonists, even though the stories are spread out fairly evenly among the cast over time. Especially for the purposes of the pilot, so if you’re writing an ensemble show like Friends, that might be a choice you have to make.
It plays out slightly differently if you’re writing a show like Modern Family, which has multiple interconnected storylines as its premise.
You will need to give each of your protagonists their own distinct plot line if you have multiple protagonists. A story with only one protagonist follows the same rules, but you’ll have to do it multiple times with fewer pages.
Because you have to complete the same amount of work in a smaller amount of time for as many characters as you consider to be protagonists, it becomes significantly more of a balancing act.
The most important aspect of screenwriting is structure. or, conceivably, of writing as a whole. Numerous books on screenwriting have been written that basically state the same thing.
They will cover it better than I can in this brief article if you want to read one. Save the Cat by Blake Snyder is the one that gets talked about the most these days. Despite the fact that I have not read it, I am unable to endorse it.
A television script’s act structure may differ from the three-act dramatic structure I’m referring to here. At the end of this article, I will discuss television structure in terms of commercial breaks. I’m going to walk us through dramatic structure right now.