C# - Validate Xml Code File Though + Use XML Serialization?

I want users to be able to export data as an XML file. Of course I want them to be able to later on import that same XML file however they always could change it or it could be a different XML file. So I want to validate the XML file to check if it is in the format that I expect. So I guess I would need something like a schema to check just that it has to be through code. So if I expect

<Root>
<Something>
<SomethingElse> </SomethingElse>
</Something>
</Root>

I don't want some other format to be in the file other then the one I expect. Also how would I validate fields? Like say I require that there must be some text in between tags. If it is blank the file is not valid. So how could I do this?

I decided to use XML serialization so I know it will through an exception if it is the wrong format and ignore stuff that does not work. However I am not sure should I just go through it and C# to validate each of the records or should I try to make an xml schema to do it. If I would want to do it through an xml schema with xml serialization how would that work? Like Do I first do something like I seen in the responses then de serialize it? Or how would I do it?