如何使用LINQ C＃正确搜索xml文档

Hey guys and gals I am having a hard time time figuring out how to properly search an xml document. I have been reading the other forms like crazy today but just can't seem to understand it. Was hopeing someone could give me a little more detailed information on how to do this the correct way and why using LINQ. Here is the XML file.Hey guys and gals I am having a hard time time