Any .net specialist arround hete?

I have an .xml file like bellow

<witd:WITD application="Work item type editor" version="1.0"
xmlns:witd="http://schemas.microsoft.com/Visual...">
<WORKITEMTYPE>
. . .
</WORKITEMTYPE>
</witd:WITD>

One of the senior devs is saying that I should validate that xml and load the schema from this xmlns:witd="http://schemas.microsoft.com/Visual..."

BUT HOW IN THE FUCKING HELL CAN I DO THAT. I found 0 code snippets that can point me in the right direction.