Variables and triggers

Hi guys - I have no doubt someone knows this - such a great community to tap into!

I have one slide with 11 graphics - I want the user to click on each graphic, which in turn then opens a layer with more information. They return to the main slide by clicking on a hide layer button and continue until they have clicked on each graphic - counter variable added (11), everything is working well. Btw, the clicking on graphics is random so I cannot add a 'show layer after [certain layer is shown]'. 

However... after the last layer of information, I would like them to return to the main slide at the count of eleven, *then* have the final 'you're finished' layer to appear (so does it need to count one more? how does it do that on a layer?). I cannot work out for the life of me as to how the last layer will show, before the final 'you're done' layer displays. I have tried all the variable (equals to, etc). nothing is working. Hope this makes sense? :| Any help is very much appreciated.. thank you!