Turn on your Mac and sign in

By the endYou can turn your Mac on, sign in, and name the three main parts of the screen.

Your Mac is the computer you will build your app on. This step takes you from a dark screen to a signed-in Desktop.

Find the power button

Where it is depends on which Mac you have.

MacBook Air or MacBook Pro (a laptop): open the lid. Recent models turn on by themselves. If nothing happens, press the key at the top-right corner of the keyboard. It is flat and blank, or has a small circle on it. This key is also the Touch ID fingerprint reader.
iMac (the screen and computer in one): the power button is a round button on the back, near a bottom corner. Reach behind the screen and feel for it.
Mac mini or Mac Studio (a small box): the button is on the back of the box, or underneath it on the newest Mac mini. The screen has its own power button.

Press the button once and let go. Do not hold it down. A screen with the Apple logo appears, then a loading bar. This can take a minute.

If the Mac is brand new

A new Mac starts with a set-up helper. It asks for your language, your country, your Wi-Fi network and its password, and your Apple Account. You can skip the Apple Account for now and add it later.

It also asks you to create a computer account: a name and a password for this Mac. Choose a password you can remember, and write it on paper. Keep the paper somewhere safe at home. You will type this password often.

Wait for the login screen. It shows your name, or a list of names, each with a small picture.
Click your name once. A box for your password appears under it.
Type your Mac password. The letters show as dots, which is normal.
Press Return, the wide key on the right side of the keyboard, sometimes marked "enter". The screen changes to your Desktop.

If your Mac has Touch ID, you can rest your finger on the Touch ID key instead of typing. After a restart, the Mac always wants the typed password once.

What you are looking at

The strip across the very top is the menu bar. At its left end is the Apple menu: a black apple shape. At its right end are the clock, the Wi-Fi symbol, and the battery.
The row of colorful icons along the bottom is the Dock. Each icon opens an app.
Everything in between is the Desktop, your work surface. Files you put there show up as small pictures.

Turning it off

You do not need to turn a Mac off every day. Closing the lid puts a laptop to sleep. To turn it off fully: click the Apple menu, click Shut Down…, then click Shut Down again in the box that appears.

If something goes wrong

Nothing happens when I press the power button. On a laptop, plug in the charger and wait ten minutes, then try again. The battery may be empty. On a desktop Mac, check that the power cable is pushed in at both ends.

The screen is black but the Mac seems on. Press any key or tap the trackpad. The Mac may be asleep.

I forgot my Mac password. Type a wrong password three times. A message appears offering to reset it with your Apple Account. Click it and follow the steps. Apple's own page lists more ways: If you forgot your Mac login password.

It typed the wrong letters. Look at the top-right of the login screen for a small flag or two letters. That is the keyboard language. Click it and choose your language. Also check that the Caps Lock key, on the left side of the keyboard above Shift, is not lit.

It asks for an Apple Account I do not know. A used Mac may still belong to someone else's account. Ask the previous owner to remove it from their account. Apple cannot unlock it for you.