Hi Srinivas,
Yes you need to use both the movement scenarios 15 & 16 to complete the STO process in TSW. Movement 15 is for transfer of a product from an origin to a transport system whereas 16 is for transfer of product from transport system to destination. For detailed flow and usage of transfer movement scenarios, please refer documentation link:
http://help.sap.com/saphelp_oil46csp2/helpdata/en/67/bfa73ad9ccf101e10000000a11402f/frameset.htm
Regards,