If you haven’t already, turn on the Email app from the Apps panel. Instructions can be found here. Then, click the “Email” app button on the OneLaunch dock.
OneLaunch's Email app provides quick access to your email with just one click! Simply hover your mouse over your most used email service provider and click the pin to add a shortcut to the OneLaunch dock. Click the shortcut anytime to instantly access your email inbox!