If you're looking to figure out what movie you want to work with (or even what particular sci-fi subgenres interest you), there are a few ways to go about it!
1. Read about subgenres: Not sure what subgenres of sci-fi interest you, or what the top films are within that genre? Consider taking a look at resources like the book linked below to start brainstorming.
2. Browse Sci fi movies on your streaming platform: Kanopy, Netflix, and other streaming services let you browse movies by genre. If you're already in a platform and deciding on what to watch, consider sorting through the available sci-fi and seeing what sounds most interesting.
3. Start with something you like, and go from there: Similar to receiving a suggestion for other books to read (long an established feature in Amazon, Goodreads and Novel), many streaming services like Tubi and YouTube will play movies that are similar to the one you just watched. Although not the most efficient way of selecting movies, it can be a fun way to discover new things. So watch something you like, and see what comes up next.