Creating Stacks from a Dash Search

I just went through the steps to install Dash Beta, Chrome extension and Windows desktop app.

Some sort of introduction screen appeared asking me to generate a stack. When the results appeared it asked if I wanted to "Keep" the stack or generate a new one. That was nice, and Keeping the stack kept all the search results that had been generated.

Now I cannot re-create that system which seems odd. What am I missing?

I want to do a search in Dash, have all the results presented to me and then add all of those results to a new Stack. 

I can create a stack, giving it a name and color. And I can add a single "Item" to the stack but I cannot find a way to add multiple search results to a new or existing stack -- as was shown to me in the introductory screens explaining Stacks. Adding to stacks item by item would be tedious, time consuming and seemingly defeating the purpose of an AI assisted search.

Can anyone explain how to do this? Thanks.