welcome top the forum, I would just point out however this forum is just for dotnetnuke issues, can ou clarify exactly what you are trying to achieve and what the connection is with your schema and dotnetnuke?

Secondly the code yuo need kind of depends on what you've been using to create your schema, did you just straight type it in notepad?

Here is some sample instructions from another site, might help you, but not sure;

Create a project to contain the XML schema file. If you intend to generate Java™ beans from your XML schema, we recommend you create a project that is configured to work with Java source to contain both the XML schema and the beans (the beans must be contained in a project configured to work with Java source, however, the XML schema does not have to be). Otherwise, it does not matter what kind of project you create. 
Select the XML file you want to create the XML schema from. Right-click it and click Generate > XML Schema. 
Select the folder or project that will contain the schema. In the File name field, type the name of the schema, for example MyXMLXSD.xsd. You must end the name of your schema with .xsd. 
Click Finish. 
A dialog box opens, indicating that the XML schema has been successfully generated. 
The schema opens automatically in the XML schema editor. It will contain all the elements that were in the XML file you used to create the schema. You can now customize it further, adding new elements and so on.

 
Might be easier for yuo to chcuk your file hrough an xml editor as it sounds like hand coding migt be above your level at this point, I am using Liquid XML Editor but there are plenty of others to choose from if you just google it, good luck