如何从弹性搜索中获取指标中的特定字段

I have inserted the below value into the elastic search with index name:count

{
"Id": "12345",
"Count": 
{
    "Timestamp": "2019-02-21T17:21:45.257013Z", 
    "TotalInstances": 300,  
    "RunningInstances": 80
}

}

i need to fetch the value of time stamp ,total instance and running instance based on id. I am using https://olivere.github.io/elastic/