My stacks not work

Hello everybody
i have buyed a rapidweaver 6 copy 2 days ago;
I can 't see (at the beginning of every project )under the column + the stacks option ( I have two purchased it in the program ) . Why it does not appear ?
thank you

Do you have the Stacks plugin by Yourhead?
http://yourhead.com/stacks

Did you already try to hover with the mouse over “All Plugins”? You should then see it in the list of all available page types…

guys thank you all, i have understand the problem and i have solved. Infact
I haven’t download the stacks3 plugin for the program; now is all ok
thank you all again