Raspberry Pi 3/4/5 Setup

The Raspberry Pi is a full Linux computer the size of a credit card. This guide takes it from a blank microSD card to a working machine you can reach from your laptop - flashing Raspberry Pi OS, setting it up headless (no monitor) over SSH and remote desktop, and finishing with a first GPIO task.

What You Will Need

A Raspberry Pi - 3, 4, or 5
A microSD card, 16 GB or larger (Class 10 / A1 or better)
A card reader for your computer
A USB-C (Pi 5/4) or micro-USB (Pi 3) power supply
For the desktop path: a monitor, HDMI cable, keyboard, and mouse
For the headless path: just your network - Ethernet or configured Wi-Fi

Step 1: Download Raspberry Pi Imager

Raspberry Pi Imager is the official tool for writing Raspberry Pi OS (and other systems) to a microSD card.

Visit raspberrypi.com/software.
Download Imager for Windows, macOS, or Linux and install it.
Insert the microSD card into your computer using a card reader.

Step 2: Choose Device, OS, and Storage

Open Imager and click Choose Device; pick your Pi model.
Click Choose OS.
Click Choose Storage and select the microSD card.

Recommended OS choices:

Raspberry Pi OS (64-bit) for the Pi 4 and 5
Raspberry Pi OS (32-bit) for the Pi 3
Raspberry Pi OS Lite if you will run the Pi headless with no desktop - smaller and lighter
Or any distro you like (Ubuntu, Kali Linux, and others are offered)

Step 3: Configure Advanced Options

Before writing, click Next → Edit Settings. This bakes your configuration into the card so the Pi is ready on first boot - essential for a headless setup, where you cannot type anything in later.

On the General tab, set:

Hostname (e.g. raspberrypi.local)
Username and password
Wi-Fi SSID, password, and your Wi-Fi country
Locale - timezone and keyboard layout

Then on the Services tab, enable SSH and choose password authentication. This is what lets you reach the Pi with no monitor.

Step 4: Write the Operating System

Click Save, then Yes to apply the settings.
Confirm the correct storage device is selected - this erases it.
Click Write and wait for it to write and verify.
Safely eject the card when it finishes.

Method 1: Desktop Setup (with a monitor)

If you have a monitor, keyboard, and mouse:

Insert the microSD card into the Pi.
Connect the HDMI cable, monitor, keyboard, and mouse.
Connect power - the Pi boots automatically.
Finish any first-boot prompts, and you arrive at the desktop.

Because you configured everything in the Imager, most of the old first-boot wizard is already done. Skip to Update the System below.

Method 2: Headless Setup (over SSH)

No monitor needed - reach the Pi from your computer over the network.

Step 5: Boot on the Network

Insert the flashed card and connect power.
Connect Ethernet, or rely on the Wi-Fi you set in the Imager.
Wait 1–2 minutes for the first boot.

Step 6: Find the Pi and Connect

Find its address from your router, an app like Fing, or just try the hostname. Then open a terminal:

Accept the fingerprint the first time, enter your password, and you are on the Pi. A $ prompt with your hostname means you are in.

Step 7: Accessing the Desktop Remotely (RealVNC)

SSH gives you a terminal. To see the actual Pi desktop from your computer, enable VNC and use RealVNC Viewer.

Enable VNC on the Pi

Over SSH, run:

Step 8: Connect from Your Computer

Download RealVNC Viewer from realvnc.com and install it.
Create a new connection to raspberrypi.local (or the Pi’s IP).
Enter your Pi username and password when prompted.

The full Pi desktop now opens in a window on your computer - no monitor ever plugged in.

Step 9: Update the System

Whichever method you used, update before doing anything else:

First Task: Blink an LED

The 40-pin header is how the Pi talks to the physical world. Here is the pinout - mind the BCM (GPIO) numbers versus the physical pin positions.

Wire an LED:

Pin 11 (GPIO17) → 330Ω resistor → LED long leg (anode)
LED short leg (cathode) → Pin 9 (GND)

Raspberry Pi OS ships gpiozero already. Save this as blink.py and run python blink.py:

Bonus: A Light-Sensing Night Light

Add an LDR (light-dependent resistor) and the LED turns on when the room goes dark.

gpiozero does the analogue timing for you - wait_for_dark() blocks until the LDR reads below its threshold, so the loop stays simple.

Troubleshooting

ssh: Could not resolve hostname: .local names need mDNS. Use the IP address from your router instead.
Connection refused / timed out: SSH was not enabled in the Imager, or the Pi is not on the network yet. Re-check the Services tab and give it another minute.
VNC "cannot connect": VNC is not enabled, or you are on a different network. Confirm raspi-config shows it on.
Rainbow square / under-voltage warning: the power supply is too weak. Use an official one - the Pi 4/5 in particular are fussy.

Where to Go Next

Attach a Pi Camera and stream video over the network.
Drive sensors and motors from the GPIO header for a full project.
Run the Pi as a always-on home server - Pi-hole, a file share, or a web app.
Try the ESP32-CAM or Jetson Nano tutorials for other on-device tasks.