A basic rule of thumb when selecting a movie is this: 3 up, 1 down. You move "down" the list by swiping left and back "up" the list by swiping right. On your turn, you can swipe left (or down) no more than three moves. If you don't see what you like by then, you must either accept the movie you are currently on or you can swipe right (or up) one time to select the previous title. Once you swipe right, you are locked in.
All the clues you need are available on the IMDb page when you click the movie title. The year, rating, and genre(s) are all just below the title and they are "free" clues. Generally speaking, just about everything else on the IMDb page is free game to use as clues. You can also improvise clues of your own under the appropriate circumstances.
You begin giving clues and the other players attempt to guess your movie. The exact mechanics differ depending on the number of players and the type of game you're playing, but the goal is the same. Obscure clues are more fun and more points. Obvious clues are easier and less points.