I have this idea of a screenplay that has to do with Navy SEALs. However I am not familiar with them. I have also heard that as a writer one should be more inclined to write what they know about.
Should I follow this advice or can I find ways of developing this idea through research? Is it necessarily that all screenwriters have an absolute clue about what their stories venture into?
If screenwriters only wrote about subjects they knew intimately, most screenplays would be about Tetris, television or getting picked last for team sports.
Write about what interests you. If you don’t know enough about Navy SEALs, research everything you can on them until you’re a pseudo-expert. Here’s the test for whether you’ve done enough research: have you annoyed all your friends and loved ones talking about all the interesting facts you’ve learned about Navy SEALs? Great. Now you’re ready to start writing.