Add electrons one at a time and watch where they go. Each orbital holds two electrons with opposite spin, and every dot in the cloud is one possible position — not an electron, and not a surface.
Bohr put the electron on a ring at a fixed distance, like a planet. It has no path at all. The cloud is a map of where it is likely to be, and nothing is orbiting anything.
An orbital is one standing wave, and only two electrons fit in it — one spin up, one spin down. A third has nowhere to go, so the next electron starts a new orbital.
Electrons repel, so within a set of same-energy orbitals each one takes an empty orbital before any of them doubles up. That is why 2p fills ↑ ↑ ↑ before ↑↓ ↑↓ ↑↓.