Understand web query code

Hey guys, I am trying to understand this code, I was wondering if some helps so I can add some annotations.
I normally use create internet explorer but I was told to use this for api websites.

Dim URL As String, lastRow As Long
Dim XMLHTTP As Object, html As Object, objResultDiv As Object, objH3 As Object, link As Object

Dim hylink As String


    lastRow = Range("A" & Rows.Count).End(xlUp).Row

    Dim cookie As String
    Dim result_cookie As String


    For i = 2 To lastRow

        URL = "https://www.google.co.in/search?q=" & Cells(i, 1) & "&rnd=" & WorksheetFunction.RandBetween(1, 10000)

        Set XMLHTTP = CreateObject("MSXML2.serverXMLHTTP")
        XMLHTTP.Open "GET", URL, False
        XMLHTTP.setRequestHeader "Content-Type", "text/xml"
        XMLHTTP.setRequestHeader "User-Agent", "Mozilla/5.0 (Windows NT 6.1; rv:25.0) Gecko/20100101 Firefox/25.0"
        XMLHTTP.send

            Set html = CreateObject("htmlfile")
        html.body.innerHTML = XMLHTTP.responseText
        Set objResultDiv = html.getelementbyid("rso")
        Set objH3 = objResultDiv.getElementsByTagName("H3")(0)
        Set link = objH3.getElementsByTagName("a")(0)


        str_text = Replace(link.innerHTML, "<EM>", "")
        str_text = Replace(str_text, "</EM>", "")

        Cells(i, 2) = str_text
        Cells(i, 3) = link.href
        DoEvents
        
    Next