The goal of this page is one thing: get a program running on a Pico and see it work. About ten minutes. You need a Pico 2 W, a USB cable, and a computer with Chrome or Edge.
A brand-new Pico is empty. You give it its "operating system," called MicroPython, one time.
Hold down the little BOOTSEL button on the Pico, and while holding it, plug the Pico into your computer with the USB cable. It pops up like a USB flash drive.
Now drag this one file onto that drive. The drive disappears on its own, that means it worked. Done forever.
Go to viper-ide.org in Chrome or Edge. That's it, nothing to install. This is where you write and run code. It's called Viper IDE (an "IDE" is just a place to write code).
Click the connect button (top right), choose USB, and pick your Pico from the list. When it connects, you can see the Pico's files on the left and a place to type commands at the bottom.
Load the "hello world" example with
this one-click link
(it drops the file onto the Pico), then open main.py and press Run.
You'll see it print messages in the terminal at the bottom.
Change the words in the file, press Run again, and watch your change happen. That's the whole loop: edit, run, see. You're programming.
main.py even runs by itself every time the Pico gets power, with no
computer attached. That's how a finished project "ships."