Help Alias underground


Hi everybody I'm a mac OSX user,
I can't find the way to select the items in inventory when I catch more
than one (for example: bomb detector, machine gun...); the help guide in
alias underground game tells me to use [ or ], but I don't know how to
select the keys in macintosh keyboard. Please, somebody help me... I try in many ways, but nothing
:o_O: :o_O: :o_O: