1) Install neofetch from your package manager, which is dnf on Fedora, apt on Debian based distros like Ubuntu and Mint. Other systems might have their own package managers. Sudo is needed to install packages.
2) Accept the install.
3) Wait for the install to finish.
4) Run the program by typing neofetch into the terminal.
5) Show off to your friends!
Neofetch is no longer under development, so vulnerabilities may appear in the future. There are alternatives like fastfetch avalible, but they are not in all package managers. Find one that works for your distro!