Answer
Press and hold a conversation, or choose Select from its More menu. A check circle replaces each customer's picture, and the top of the list shows how many you've selected and what you can do with them. Tap other conversations to add or remove them. On a computer, Ctrl-click (Cmd-click on a Mac) adds or removes one conversation, and Shift-click selects every conversation between the last one you picked and the one you click.
In the HelperHat and Inbox tabs you can mark the selected conversations Done, move them to Trash, or mark them as read. In Done you can move them to Trash or mark them as read. In Trash you can restore them to Inbox or delete them forever. Mark as Read only shows when at least one selected conversation is unread, and moving a conversation from HelperHat or Done to Inbox works one conversation at a time.
Done, Trash, Restore, and Mark as Read happen right away for every selected conversation. If some can't be saved, they go back to where they were and one message says how many. Delete Forever asks you to confirm once for all of them, and it can't be undone.
To stop selecting, choose Close, press Escape, use your phone's Back button, or switch tabs. Swiping is off while you're selecting.