z readme, it says:
Put something like this in your $HOME/.bashrc or $HOME/.zshrc:
cd around for a while to build up the db.
You need to download the
z.sh file to a directory of your choosing, then tell your
.bashrc where it is, so your terminal can find it. (The same applies for z-shell, which is just another shell system.) Then, after you use bash for a while,
z will know your favorite locations.