Orbit isn't about going up — it's about going sideways so fast that you keep missing the Earth. This is the single most useful idea in spaceflight.
Up is the easy part
A rocket that only went straight up would coast to a peak, slow down, and fall straight back — like a very expensive ball. Space begins around 100 km up (the Kármán line), and getting that high takes only a small fraction of a rocket's effort. If altitude were the goal, spaceflight would be easy. The hard part is what happens next.
Orbit is falling — and missing
Newton imagined a cannon on a tall mountain. Fire the ball faster and faster and it lands farther and farther away — until, at one particular speed, the ground curves away exactly as fast as the ball falls toward it. The ball is still falling, forever, but it never lands. That is an orbit. Astronauts float not because gravity is gone (at the Station's altitude, gravity is still about 90% as strong as on the ground) but because they and their spacecraft are falling together, endlessly missing the Earth.
The gravity turn
This is why every launch you watch bends over within the first minute. The rocket climbs just long enough to escape the thickest air, then pitches over and spends most of its fuel accelerating horizontally, chasing that magic sideways speed — about 7.8 kilometers every second for low Earth orbit, roughly 25 times the speed of sound. Watch any webcast and you'll see the callout for it: the vehicle isn't going up to space, it's going around to it.
What to watch for
On your next launch stream, watch the speed and altitude readouts instead of the flames. Altitude settles down early; speed keeps climbing all the way to orbit. When the announcer says the vehicle is 'downrange', that's the sideways journey in action — hundreds of kilometers across the ocean while only a couple of hundred up.