You would use MyBatis with Struts the same way you would work with it in any other Java application. Can you write a simple Java app to use MyBatis? If so, how are you using it differently with Struts? If not, you need to start with learning MyBatis.
As I told you in your previous post, we need more information if you want more specific help from us. The better question you ask, the more help we can give.