Step 1

Download the OS from here: https://www.raspberrypi.org/downloads/
Download the etcher from here: https://www.balena.io/etcher/
Extract the image file from downloaded OS
Plug your sd card into the system
Open the etcher, select the image and your sd card
Press flash button
Congo!! you have successfully booted os on sd card.

Step 2

Now we need to create two files in raspberry pi boot folder inside the sd card.
First create a file named ssh (without any extension) using this command.
```
touch ssh
```
Create second file named wpa_supplicant.conf

ctrl_interface=/var/run/wpa_supplicant
update_config=1
country=<Insert country code here> # IN (INDIA)

network={
 ssid="<Name of your WiFi>"
 psk="<Password for your WiFi>"
}

Now insert the sd card into your raspberry pi and power it on.

Step 3

Now we need to find the IP address of raspberry
Install nmap using this command
```
sudo apt install nmap
```
Now get your system ip address using command ifconfig
Now scan your whole network using the command below
nmap -sn <your ip address>/24
Note: replace your ip address last digit with 0. For example: 192.168.41.16 with 192.168.41.0
Now you need to manually identify the ip address of your raspberry.
To verify the ip we need to ssh into the raspberry pi with each ip.

Step 4

For each ip ssh using the below command
```
ssh pi@<ip address>
```
Default password is raspberry
Now you have successfully logged in to your raspberry pi

Step 5

Now you are logged in as user pi , which is the default user
Enable the root user for login using ssh
First Login with pi user using default password which is raspberry
Now write this command to login as root
```
sudo su
```
Now edit the file /etc/ssh/sshd_config using below command
nano /etc/ssh/sshd_config
Change the text #PermitRootLogin without-password to PermitRootLogin yes
Now save and exit file
Now to write the below command to restart ssh service
```
/etc/init.d/ssh restart
```
Now set your root password using the below command
```
passwd root
```
Now enter your password.
Once you have succesfully set the password, you can login to raspberry as root user using the below command
```
ssh root@<raspberry ip address>
```