Users access the Work Orders home page from the Recent section of the Salesforce1 navigation menu. To locate this item, it may be necessary to expand the Recent section by tapping More. Work Orders is automatically included in the navigation menu as part of the Smart Search Items element. See Salesforce1 Mobile App Navigation Menu in the Salesforce Help for information about how the navigation menu is populated.
To learn more about work orders, see Go Forth, Field Technicians: Introducing Work Orders (Generally Available).