It was at nighttime, and my brother and I were standing in the front yard / driveway area of our father's house. There may or may not have been other people. In the night sky, we could see a red celestial body, which looked like the moon (though reddened), although it was slightly smaller than usual. We weren't sure whether it was really the moon or maybe a planet in the solar system. In the dream, I think I was noticing how similar it was to Biblical prophecy about the moon turning red.
I and possibly my brother were trying to get our father to come outside and see this very interesting sight. He kept delaying coming out of his house, and I was getting annoyed. I didn't disrespect him, but was irritated with him and wanted him to see it before it potentially went away.
What had previously looked like the moon, though red and slightly smaller, then got a lot bigger and had a lot more yellow and orange; it looked like fire, and it looked like the sun (though a lot bigger). We were wondering whether it was some other star somewhere else that had blown up and died long ago, and maybe now the light from the event had finally made it to Earth so we could watch it occur.
Then it turned mostly black and green, into some different shape, and somewhat smaller. It looked like an alien spaceship, and it started flying towards Earth. My father may or may not have finally come outside at the last second, but either way, my brother and I just ran back in the house with our father. Whether other people were outside earlier or not, they did not come in with us.
The object turned out to indeed be an alien spaceship, and since it was First Contact, the obvious question was this: Do they come in peace or in hostility? Either way, we went into the den with our father, where he had some guns. He started handing each of us a gun, and he handed us bullets. The bullets though were not high-quality, military-grade ammunition. They almost looked clay, stone, or earthen, kind of like Civil War bullets. They looked like you could just throw them up against a wall, and they would likely just crumble. They still worked the same way as modern bullets though, and as weak and low-grade as they were, they could be used to kill somebody if they were fired from a gun.
Basically while we were in the house, and the den in particular, the spaceship landed in the next door neighbor's yard. The blinds in at least that part of our father's house generally tended to be closed, so we couldn't see much outside, and the aliens couldn't really see us. But we could still hear things and could maybe see just enough to know it had happened. Just as soon as we had received our guns and ammunition, we could hear the aliens outside yelling and stuff. Over a loudspeaker or something, we could hear them announce to the resident(s) of that other house that they were occupying it militarily, that they were basically going to use it as their base (whether it was their main HQ or not), and that the neighbor(s) had to get off the property.
The unspoken, yet obvious question from before had been answered: The aliens had come in hostility. We were going to need to fight them.