To work with SAP Work manager you need to install Agentry server which is included in SMP 2.3 .
please check the below documents for the implementation details
details of Release Notes and addons
SAP Work Manager 5.3 Extended Feature List | SCN
Troubleshooting: SAP Work Manager 6.0 Attach Document issue
Deploying Work Manager 6.0 on SMP 2.3 | SCN