sudo apt install fonts-powerline
sudo apt install zsh
sh -c "$(curl -fsSL https://raw.githubusercontent.com/robbyrussell/oh-my-zsh/master/tools/install.sh)"
chsh -s $(which zsh)
The function will not be run in future, but you can run it yourself as follows:
autoload -Uz zsh-newuser-install zsh-newuser-install -f