zsh completion installations (autojump) - How to use them?
Oh-my-ZSH config file should have a line starting with plugins=, like this:
plugins=(git gitignore autojump jira command-not-found zsh-syntax-highlighting)
Whatever you put there is considered by ZSH to be an active plugin.
In case of AutoJump, oh-my-ZSH Plugin Wiki states that:
Enables autojump if installed with homebrew, macports or debian/ubuntu package. This does not add any commands on its own.
Config file you are looking for: .zshrc
EDIT:
Note that some folks claim FASD is better, if autojump won't work for you, you may try FASD instead.
Thanks @Adaephon, added link to source of the quote and marked it's oh-my-zshell rather than pure ZSH.