How to add multiple attribute and corresponding values within xml child node

Add multiple attributes and values to a xml child node.
Ex- I want to add another Rule within Namespace element.

<GlobalAppSettings 
  <NameSpace name="retail" 
  </NameSpace>
  <NameSpace name="APEService" inheritsFrom="retail">
	<Rules>
	  <Rule namespace="retail" queues="Default" scanInterval="10000" threads="2" />
	  <Rule namespace="retail" queues="DLS" scanInterval="9000" threads="1" />
	 
	</Rules>
  </NameSpace>
</GlobalAppSettings>

I tried adding another element and a text node but am stuck at this point and unable to proceed.

You can use the
System.Xml.XmlDocument
to accomplice this

here is an example of how to add an extra rule to your mentioned xml

$pathToXml = "C:\temp\xml.xml"

$xml = New-Object System.Xml.XmlDocument
$xml.Load($pathToXml)
$namespaceNode = $xml.SelectSingleNode("//NameSpace[@name='APEService']")
$rulesNode = $namespaceNode.SelectSingleNode("Rules")

# Adding a new rule:
$ruleNode = $xml.CreateElement("Rule")
$ruleNode.SetAttribute("namespace", "retail")
$ruleNode.SetAttribute("queues", "sometimes")
$ruleNode.SetAttribute("scanInterval", "8000")
$ruleNode.SetAttribute("threads", "2")
$rulesNode.AppendChild($ruleNode)

# Removing a rule:
# Select the rule to be removed by the queues name 
# if you need to remove a complete namespace you could just use @namespace instead of @queues
$ruleToRemove = $rulesNode.SelectSingleNode("Rule[@queues='DLS']")

# Remove the rule from the parent node
$rulesNode.RemoveChild($ruleToRemove)

$xml.Save($pathToXml)