JQ filter for a single JSON file

I have a file containing

{
  "solr.jetty": {
    "org.eclipse.jetty.server.handler.DefaultHandler.requests": {
      "count": 432742,
      "meanRate": 0.1393530774422645,
      "1minRate": 0.1582358234691172,
      "5minRate": 0.24472281886082692,
      "15minRate": 0.32856666658514566,
      "min_ms": 0,
      "max_ms": 124,
      "mean_ms": 19.05039312538189,
      "median_ms": 1,
      "stddev_ms": 27.68447649619781,
      "p75_ms": 61,
      "p95_ms": 63,
      "p99_ms": 64,
      "p999_ms": 67
    }
  }
}

I want jq command to print the "count" field.

I read many web pages with a lot of dumb examples and I didn’t get yet my filter to use because I find it all very counterintuitive.

P.D: do you know any good jq tutorial or guide?