Not only is this what's happening at the beginning, which should tip you off that it's the initial situation, it's also an obvious set-up. A wild demon attacking a defenseless group of people? It's time for a hero to come on the scene and put this to rights.
How much more obvious can a conflict get? We've got two guys in a no-holds-barred wrestling competition to the death. If that's not a conflict, we don't know what is. Beowulf isn't usually very subtle about these things.
This is just the kind of frustrating thing that happens to you when you're a heroic Geatish warrior. Here you are, going all-out and wrestling a demon to the death, and just when you think you've won and you have a few minutes to get drunk and celebrate, the demon's mom comes along and gets her panties in a twist because you killed her kid. We love mothers, but they do seem to make things complicated sometimes.
Just when you think Beowulf is going to live happily ever after, he has to face his greatest challenge yet: a fifty-foot-long firebreather. If anything screams "climactic battle scene," it's the arrival of a dragon.
If you're tempted to yell, "Just get on with it!" at this point, you're not the only one. Beowulf hangs out for several hundred lines, talking about his past glories and wondering if he's going to die while fighting the dragon. Still, it does help to build suspense, because it makes us wonder, too.
It's a double-whammy: Beowulf dies, but so does the dragon. After that, it's obviously all downhill, so this is definitely the denouement.
Is anything more conclusive than a funeral? Beowulf is dead, and after mourning his death and celebrating his heroic deeds, the Geats look to the future. Of course, without his protection, it's a pretty bleak future.