I think anyone who's had an interest in the Beatles or the 60s as a whole has seen footage of the week long "Bed In" held by John and Yoko in a Montreal hotel. This film is Yoko's personal cut of the events. It is of interest to see what she felt was worthy of inclusion in comparison to other depictions, but it isn't a particularly useful anti-war device.
We see the room before the press arrive in long, slow, quiet shots, and then get a Yoko song as sound track as the press scuttle in and erupt in a chatter of questions. The choice to give the song more volume than the questions depicts a dislike for how the media was treating the couple. As the song ends, the paces slows, and we get some longer shots again. This transitions to one-on-one (well, one-on-two, really) conversations between a guest and the pair. The pair talk about ending war with peace and love. They freely admit they don't have all the solutions, but suggest that the guests has intelligence, and can create peaceful solutions for themselves -- they don't have to follow the failures of the past, think up something new.
Told of the Berkley situation (police coming in to close the park), John gives a long-distance call-in to a radio station that the kids should just leave -- there's no need to kill yourself over a park. Go anywhere. If they kick you out of one place, find another. Yoko joins in by saying that as they move, they will leave there footprints behind, and make the world a better place. It does not seem to occur to anyone that the institutions of authority will merely develop more effective methods to stop future protests.
John is one of the only four people who could ever say the lines, "All you need is love", "Come together", and "Give peace a chance" and sound credible doing so. Time and the then-future presidency make a reference to "old politicians like Reagan and Nixon" seem sadly naive.
Much of the film is comprised of montages. The full song "Give Peace a Chance" is included, but only the beginning and end have corresponding footage of the song's singing. There are (at least) two more complete songs that drown out all dialog, and most of what is said is more of the original message. Create a new solution based on Love and Peace. There are also some bits of intimacy between John and Yoko, but the camera is an intruder on those events. John really seems to resent it and tells the cameraman to go away.
Most any documentary about the event will be more informative, so only watch this is you are a serious Beatles fan. It is not required viewing for anyone else. Oh, if you are a film student, you might enjoy how they did the end credits (low budget and interesting in a college-level way).