robin Williams committed suicide last year but staring in a movie that's coming out at august the 14th how does this work Im very confused?

the movie was probably still in production, or filming was done and was being edited when he died. Same situation for the last Night at the Museum movie. If you haven't seen it yet there is a tribute to him at the end of the movie

Sometimes movies are made far in advance. Sometimes they are made more than a year before their actual release date

The scenes would have been filmed before his death. Once all filming has been done, there is still a lot of work, called post production, to be done, so a movie that has been filmed a year ago or more may only just be coming to cinemas.

The movie was filmed before he died, but published after his death.

They recorded the movie before he committed suicide

His ghost is the star obviously...duh..
Um no; just means he filmed plenty of movies before he died.

Movie was in post production + waiting for the studio's timed release.

How is this confusing? He did his work in the movie. Then some time after that he hanged himself, and now the movie is coming out.

Are you confused about the delay? Nothing weird about that. Movies take time to make