Here is a video of the 1945 parade. Since you probably don't understand what's going on, I will point you to specific clips. I wish I could sit beside you and point out specific things and translate as the video plays.
1:22 Holding the Nazi flags that they've "captured"
2:30 Stalin is one of those important guys, overlooking the parade. A few moments later is when the parade actually begins, but you can fast forward to 4:57, where there is a gun salute. Then they all march, grouped by their "fronts" -- 1st Belorussian front, for instance. After a few moments of that, switch to the Part 2 video.
Part 2 of the 1945 Victory Day Parade:
0:59 Throwing the Nazi Germany banners in a pile (watch until 1:29)
I never realized how massive this parade was -- the clips of these videos shown in the War Museum only total about 5 minutes, if that! I just finished fastforwarding through these videos, and I couldn't really find them yelling "Hoorah!" like in the museum's clips. Sorry about that -- you'll just have to come here and see the clip for yourself at the museum. :)
Yesterday I walked around the National Botanical Garden with a friend, and the place was packed! People were enjoying the sort of-nice spring weather and the holiday weekend.