To process Change Set deployment from a Sandbox to a production org, follow the instructions listed below
1.Log in to your sandbox.
2. Enter Outbound Change Sets.
3. Click New.
4. Enter the new Change Set and description, then click Save.
5. From the “Change Set Components” related list, click Add.
6. Add profiles to the Change Set for the Users you’d like to grant access.
7. Select the “Component Type” for the component you want to deploy (for example, Apex class, Apex Trigger).
8. Select the specific class or trigger name, then click Add to Change Set.
9. From the “Change Set Detail” related list, click Upload, then select the target Organization as Production.
10. Click Upload.
1. Click Setup | select App Setup | Inbound Change Sets.
2. Under “Change Sets Awaiting Deployment,” click your Change Set’s name.
3. Click Validate to validate your code. Note: For successful deployment you should have at least 75% code coverage.
4. Click Deploy.