Using LSMW 
Prerequisites
Data migration comes in the end of the SAP implementation. Ideally, you must have already installed the SAP system and completed the Customizing settings for your applications.
A basic knowledge of ABAP programming is useful when you migrate external data to the SAP system with the LSM Workbench.
Process Flow
Administration
The LSMW includes a range of administration tools that you can use to configure, monitor, document and test the migration of your data.
Data Migration
The actual data migration process is simplified as a sequence of fixed steps. On the initial screen of the LSM Workbench, the next step is displayed automatically.
More Information
For details about working with the LSM Workbench, see the following:
IDoc Inbound Processing