Steps of initial stock entry in SAP WM
1. Initial stock upload with transaction MB1C (Movement type 561)
Post the material document
2. Post stock transfer from storage type 998 to OPS (from interim storage type to storage type whcih you want to place)
Press enter
3. Confirm TO with transaction code LT12
After all above steps finished, you can find the WM stock with transaction code LX02.