Do you mean the button to start bounce processing? If so, that's at the bottom of the Tokens table. See screenshot below. Note that using the gartergrey or blobblueish templates this button was missing (actually just the icon), but that's been fixed in LS Version 2.00+ Build 120926.
NOTE: I've tried repeatedly to upload the image as an attachment but the forum won't do it. So here's a link to it:
Last Edit: 4 years 4 months ago by bradummer. Reason: link to image