Check if xml exists in a directory and read it

Question

Hello everyone I'm new to c#. I want to read an xml file if it exists in a directory. 1) How can I read it? 2) If there are multiple xml files how to read those at the same time?

        XmlTextReader xtr = new XmlTextReader(path)
        string pathD = @"H:\UsersDirectory";
        DirectoryInfo di = new DirectoryInfo(path);
        FileInfo[] TXTFiles = di.GetFiles("*.xml");
        if (TXTFiles.Length != 0)
        {
            //how can I read the file?
        }