Using html agility pack, how can I obtain the text from a nested p> element in an external html?

I'm attempting to get some text from an outside website. I'm attempting to extract text from a paragraph tag. There is a class value for the div.

HTML code example

<div class="discription"><p>this is the text I want to grab</p></div>

existing C# code:

public String getDiscription(string url)
{
    var web = new HtmlWeb();
    var doc = web.Load(url);


    var nodes = doc.DocumentNode.SelectNodes("//div[@class='discription']");

    if (nodes != null)
    {
        foreach (var node in nodes)
        {
            string Description = node.InnerHtml;
            return Description;
        }
    } else
      {
       string error = "could not find text";
       return error;
      }
}

What I don't understand is how the xpath syntax works.//div[@class='discription'] I am aware that that is incorrect. What must the xpath contain?