Reviews come out when a film premieres or is released.
It's fairly easy to find reviews of current films using an online database or the internet.
It's not so easy to find reviews of films that came out before 1980, and the older the film, the more places you may have to look.
Knowing the year a film came out will make your work easier, especially if you're looking for reviews of older films.
If you're not sure of a film's title, you can search by director or actors or other people associated with the film.
These Internet resources are especially useful for finding reviews of newer films: