How to go from an episode idea to structuring scenes

We've all been there. You have an idea for a sitcom that you absolutely love... featuring a bunch of silly, zany characters with complex emotional arcs and ideas. You maybe even have an idea for an episode, but when you sit down to write it, you have no idea how to start. Do you just start typing out dialogue in the hope that it will lead somewhere good? Do you have to create some kind of complex mood board involving photos of your characters and bits of string, like something you'd find in a paranoid detective's basement? Do you give up and watch an old episode of Diagnosis Murder instead?

You have so much that you want your characters to do and think and say, but fitting all of that into the actual structure of an episode feels impossible. How do you go from that first spark of an idea and turn it into a fully living breathing episode with emotional beats, scenes and dialogue? Let's dive in and find out!