Method 2: For amd64, i386, armel, armhf and arm64 architectures (Main repository)

Add the following into /etc/apt/sources.list. To edit /etc/apt/sources.list, you can type
sudo nano /etc/apt/sources.list
Add the following to the top of /etc/apt/sources.list. Ensure you replace bullseye with your respective OS release.
deb http://mirror.coganng.com/debian bullseye main
deb-src http://mirror.coganng.com/debian bullseye main
Ensure you replace bullseye with your respective OS release.To check your OS release, type
. /etc/os-release && echo "$VERSION_CODENAME"
into a Bash terminal.