This means the components for the service is available. You need to add the service in Service Registry. For that
1. First check the system alias configuration. Refer to SAP Fiori LL06 - Define system alias for the TA... | SCN (as suggested by Virinchy P)
In your case as everything is in the same box you can keep the RFC Destination field as empty(refer to http://scn.sap.com/servlet/JiveServlet/showImage/38-87743-236066/system_aliases2.png).
2. Now go to /IWFND/MAINT_SERVICE.
3. Now refer to section "to Activate the service" in "Configuring the Task Gateway Service - SAP NetWeaver Gateway - SAP Library" and follow from Step 5.