I struggle with the XML road.
So, if you want to understand better how the XML works, I recommend you to read the XML manual from Construct website. Then, you'll notice the following phrase from there:
It uses XPath to access the XML document.
Then, check this website to understand XPath. It is quite simple with lots of examples and shouldn't take you too much time.
Okay, having said that... The XML syntax follows a hierarchical rule. When you want to retrieve a value from an XML element you need to correctly follow the path from your nested tags. For example:
Imagine you want to get the value from the tag <A> which is within the tag <1>. Because <A> is nested within <1>, and <1> is nested within <Niveau>, you have to follow the hierarchical path. That's why the path to get the StringValue is "/Niveau/1/A/text()".
Instead of "1" and "A" I want to put the name of the sprite in the XML line.
From what I understand, you would like to do this?