Hi,
Please clarify your question..
1. Whether the client 200 and 300 are in different systems like DEV & QUA. or
2.Whether the client 200 and 300 are in the same system like DEV ONLY.
If the option 1 , then please go ahead with the steps that are mentioned in the below link.
http://www.sapbasismania.net/2012/11/how-to-configure-sap-transport-route.html
It has step by step screenshot on how to configure STMS and SAP Transport route.
If the option 2 , please use SCC1 tcode after login to 300 client , provide TR and import it in your 300 client.
Thanks and Regards,
Vimal
