Drop .zsh-theme file into your themes directory
/Users/TW/.oh-my-zsh/themes/marmalade.zsh-theme
Point to the theme in .zshrc
# Set name of the theme to load.
# Look in ~/.oh-my-zsh/themes/
# Optionally, if you set this to "random", it'll load a random theme each
# time that oh-my-zsh is loaded.
ZSH_THEME="marmalade"