how to use Substrate RPC metrics in Grafana

Question

I need to use substrate_rpc_calls_time, substrate_rpc_calls_started, substrate_rpc_calls_finished to show RPC metrics on Grafana dashboard.

I added following section in my prometheus config file:

{
      "datasource": "${DS_SUBSTRATE_NODE}",
      "description": "Total time [μs] of processed RPC calls",
      "fieldConfig": {
        "defaults": {
          "custom": {},
          "mappings": [],
          "thresholds": {
            "mode": "absolute",
            "steps": [
              {
                "color": "super-light-yellow",
                "value": null
              }
            ]
          }
        },
        "overrides": []
      },
      "id": 20,
      "options": {
        "colorMode": "value",
        "graphMode": "none",
        "justifyMode": "auto",
        "orientation": "auto",
        "reduceOptions": {
          "calcs": ["last"],
          "fields": "",
          "values": false
        },
        "textMode": "auto"
      },
      "pluginVersion": "7.3.6",
      "targets": [
        {
          "expr": "substrate_rpc_calls_time",
          "interval": "",
          "legendFormat": "",
          "refId": "A"
        }
      ],
      "timeFrom": null,
      "timeShift": null,
      "title": "Total time [μs] of processed RPC calls",
      "type": "stat"
    }

Can someone please help me fix this?