A: It's rather hard to explain to a person who's country has never been invaded.
Consider one simple fact: nearly every single person in that audience has lost a relative
(whether close or distant) in that war. Try looking at the recap of the events depicted, provided below -- maybe it will help?
Q: Can somebody annotate the events in the video?
A: Here you go:
0:00-1:30: A peaceful evening somewhere in the eastern USSR (whether Ukraine, Russia or Belorussia, it's not clear from the picture). He and she are sitting in the city park, a large Christian Orthodox church can be seen in the distance.
1:30-2:00: A lightpole-mounted radio speaker appears and announces German invasion into the USSR (June 22nd, 1941), German bombers appear in the air. She's scared and crying. A patriotic song calling all citizens to arms is played, and her mate obvuiosly heads out to protect the Motherland.
2:00-2:20: Troops are marching out of town, boarding trains and heading out to the frontlines.
2:20-3:05: The kid is born and she takes care of him during the long nights; her tears disappear, replaced with a loving smile.
3:35-3:40: Not quite clear. Could either mean that she and her kid end up under German air raid facing the scary turnmoil, but escape alive. Or, it could represent him battling with the enemies (in the wartime propaganda pictures, German Nazi were often depicted with those ugly pointy noses).
3:40-4:10: She receives a letter from the frontlines. Could it be from him? She's hopeful.
4:10-4:40: The letter announces that he's dead. The harsh news turn the beautiful girl into a sorrowful old lady.
4:50-5:05: His grave. Some people in the comments claimed that it's a Monument to Unknown Soldier. The confusion is understandable, given that these monuments were made to resemble the soldier graves (only scaled up). In other countries, it is common to mark their fallen by crosses; in the USSR, it used to be a wooden or metal pyramid (obelisk) crowned by a star. I am unable to find a photo of one from 1940's, but here's a more recent one to give you a general idea. See also this and this (frames from a movie).
5:05-5:30: We can see an old lady mourning him; I would assume it's his mother. Soon she's joined by our girl and their little son.
5:30-6:40: A citi razed to the ground by the war is slowly rebuilt.
6:40-7:10: She oftentimes looks out of the window, still hoping that was a mistake and he is not actually dead and will one day return...
7:10-7:40: She sees his image in the glass... In that image, he wears the Russian sailor's uniform so we can conclude he was a sailor.
7:40-8:10: Their little son joins his mom in looking out of the window... he also wears the kid version of sailor's uniform, so he'll obviosly go in his father's footsteps...
8:10-END: Conclusion of the... movie? "You are forever beside us. 1945."
Q: What did she spell out in the end?
A: "Ты всегда рядом" (in Russian). Different translations are possible, the one
I think is the best is "You are forever beside [me/us]";
can also be translated as "You are always near", "You are always close",
"You are always next to [me/us]", etc.
Q: What does 1945 mean?
A: The year when World War II (or, more precisely, the Great Patriotic War
which is relevant for the USSR/Russia/Ukraine) has ended. This number has a very
special meaning for Soviet people/Russians/Ukrainians, a reminder of a great victory
earned in great struggle, at the cost of great losses.
A: This is the actual historical broadcast making citizens of the Soviet Union/Ukraine/Russia aware of the German invasion on June 22nd 1941. See the original recording.
Q: What is the jingle precluding the radio announcement (@ 1:27)?
A: It is a Soviet-era radio jingle that precluded newscasts since 1939. It's the first few chords of "Широка страна моя родная" ("Broad My Dear Country Is") -- listen to the
full song on YouTube, read Wikipedia article (in Russian, use Google translate to read if you want). The
MP3 of the jingle itself can be downloaded here.
Q: What is the song @ 1:45 playing along with the radio announcement?
A: "Священная война" ("The Sacred War"), an inspirational song written in 1941 shortly after the German invasion of the USSR; it has been later famously performed by the A.V. Alexandrov's Red Army Choir. Read more about it on Wikipedia. Watch video on YouTube. Sovmusic.ru has it as an MP3 file.
A: "Журавли" ("Cranes"). This is a song of a soldier who lived to see the end of war and is now mourning his fallen comrades. Full song here. Read Wikipedia article. Translation (googled somewhere and improved by yours truly to rhyme better):
It seems to me sometimes that all the soldiers,
Who never came from bloody fields of war,
Were not just laid into the dirt, but turned
Into the cranes of color snow-white.
So they are flying ever since those ages;
They call to us, and may be that is why
We hear their cries, so full of burning sadness
And we fall silent, gazing at the sky.
The flock is flying, crying, sad and tired,
Through fog, through mist, in quiet light of dawn
And I can see that there is a gap amongst them.
Was it reserved for me? It could be so...
There will be day and I will fly right there,
There will be day -- and maybe it is close.
And from the skies above I will be sending
Same call for those of you I left below.