To install zsh follow the steps on the official website: https://ohmyz.sh/
Cloning repository
$ git clone https://github.com/gersontpc/zsh-theme-grs.git
Copy the theme to the zsh themes directory
$ cp zsh-theme-grs/grs.zsh-theme /home/your-user/.oh-my-zsh/themes/
Changing the GRS theme
$ vim ~.zshrc
ZSH_THEME="grs"
Applying the theme
$ source ~.zshrc