Missing the plugin stack?

I just bought my first stack and after I downloaded it and tried to add it to my page, I get this message… The “Stacks” Plugin is missing. Can I not use the stack or what?

To use stacks in RW you need to have the main Stacks plugin, currently Stacks 3. Have you bought and installed that?


No, I haven’t… new to this. Thank you so much for you help!