You can use the following keyboard shortcut:
Alt + Shift + 1 Display OneTab
If you would like to change these keyboard shortcuts, right click on the blue OneTab browser toolbar icon, click 'Manage', then at the bottom of the page click 'Configure Commands / Keyboard Shortcuts'.
You can also set your own keyboard shortcut to mimic the effect of clicking the blue OneTab icon which will send all tabs in the current window to OneTab. To do this, from the keyboard shortcuts settings screen described above, specify a shortcut in the box where it says "Activate the extension".