How to get list of XML nodes via XPath which has XmlNamespace?

Question

Visual Basic

I'm trying to find `complexType` elements in an XSD document via `XPath`.
But I clearly don’t understand how namespaces work and how to set up `XmlNamespaceManager`

_document = New XmlDocument()
        _document.Load(current_xsd)

        Dim nsmgr As XmlNamespaceManager = New XmlNamespaceManager(_document.NameTable)
        nsmgr.AddNamespace("xs", "http://common")

        Dim nodeList As XmlNodeList = _document.SelectNodes("//complexType", nsmgr)

        For Each node As XmlNode In nodeList


        Next

Document part:

<?xml version="1.0" encoding="utf-8"?>
    <xs:schema id="Catalog" targetNamespace="http://catalog" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xc="http://common" xmlns="http://catalog">
      <xs:import namespace="http://common" schemaLocation="Common.xsd"/>
      <xs:complexType name="brigade">
        <xs:complexContent>
          <xs:extension base="xc:extraFieldContainer">
            <xs:sequence>
              <xs:element name="brigadier" type="staffPersonnelNumber" minOccurs="1" maxOccurs="1"/>
              <xs:element name="employees" type="employeCollection" minOccurs="0" maxOccurs="1"/>
            </xs:sequence>
            <xs:attribute name="name" type="xs:string" use="required"/>
          </xs:extension>
        </xs:complexContent>
      </xs:complexType>
      
    </xs:schema>