Explore: add URL schema docs (#71724)

Co-authored-by: Kristina <kristina.durivage@grafana.com>
Co-authored-by: Piotr Jamróz <pm.jamroz@gmail.com>
Co-authored-by: Kim Nylander <104772500+knylander-grafana@users.noreply.github.com>

docs/sources/explore/_index.md

@@ -64,6 +64,46 @@ In split view, timepickers for both panels can be linked (if you change one, the
 
 To close the newly created query, click on the Close Split button.
 
+## Share Explore URLs
+
+When using Explore, the URL in the browser address bar updates as you make changes to the queries. You can share or bookmark this URL.
+
+### Generating Explore URLs from external tools
+
+Because Explore URLs have a defined structure, you can build a URL from external tools and open it in Grafana. The URL structure is:
+
+```
+http://<grafana_url>/explore?panes=<panes>&schemaVersion=<schema_version>&orgId=<org_id>
+```
+
+where:
+
+- `org_id` is the organization ID
+- `schema_version` is the schema version (should be set to the latest version which is `1`)
+- `panes` is a url-encoded JSON object of panes, where each key is the pane ID and each value is an object matching the following schema:
+
+```
+{
+  datasource: string; // the pane's root datasource UID, or `-- Mixed --` for mixed datasources
+  queries: {
+    refId: string; // an alphanumeric identifier for this query, must be unique within the pane, i.e. "A", "B", "C", etc.
+    datasource: {
+      uid: string; // the query's datasource UID ie: "AD7864H6422"
+      type: string; // the query's datasource type-id, i.e: "loki"
+    }
+    // ... any other datasource-specific query parameters
+  }[]; // array of queries for this pane
+  range: {
+    from: string | number; // the start time, in milliseconds since epoch
+    to: string | number; // the end time, in milliseconds since epoch
+  }
+}
+```
+
+{{% admonition type="note" %}}
+The `from` and `to` also accept relative ranges defined in [Time units and relative ranges]({{< relref "../dashboards/use-dashboards/#time-units-and-relative-ranges" >}}).
+{{% /admonition %}}
+
 ## Share shortened link
 
 {{% admonition type="note" %}}