Add more than one email to a box by selecting multiple threads in your inbox and adding them to a new or existing box in the sidebar.
Check the boxes next to each email that you would like to add to a box.
Click the orange plus button at the top of your inbox.
Create a new box in one of your pipelines, select a suggested existing box, or search for an existing box in the sidebar.
After associating the email thread(s) to a box, you will see streak inbox labels indicating which pipeline and stage the boxed email is in.