Obtained from a Linux.com tutorial.
zf#j: creates a fold from the cursor down # lines.
zf/string: creates a fold from the cursor to string .
zj: moves the cursor to the next fold.
zk: moves the cursor to the previous fold.
zo: opens a fold at the cursor.
zO: opens all folds at the cursor.
zm: increases the foldlevel by one.
zM: closes all open folds.
zr: decreases the foldlevel by one.
zR: decreases the foldlevel to zero -- all folds will be open.
zd: deletes the fold at the cursor.
zE: deletes all folds.
[z: move to start of open fold.
]z: move to end of open fold.