[Dashboard links] Links documentation (elastic#170153)

Fixes elastic#166750

## Summary

Adds documentation for the links panel.

---------

Co-authored-by: Amy Jonsson <[email protected]>
(cherry picked from commit 878df86)

docs/user/dashboard/make-dashboards-interactive.asciidoc

@@ -211,6 +211,70 @@ To use series data interactions, click a data series in the panel.
 +
 To use saved search interactions, open the panel menu, then click *More > View saved search*.
 
+[[dashboard-links]]
+=== Create links to other dashboards
+
+preview::["This functionality is in technical preview, and may be changed or removed in a future release. Elastic will work to fix any issues, but features in technical preview are not subject to the support SLA of official GA features."]
+
+You can use *Links* panels to create links to other dashboards or external websites. When creating links to other dashboards, you have the option to carry the time range and query and filters to apply to the linked dashboard. Links to external websites follow the <<external-URL-policy,`externalUrl.policy`>> settings. *Links* panels support vertical and horizontal layouts and may be saved to the *Library* for use on other dashboards.
+
+* <<add-links-panel, Add a links panel>>
+* <<add-links-panel-from-library, Add a links panel from the library>>
+* <<edit-links-panel, Edit links panels>>
+* <<delete-links-panels, Delete links panels>>
+
+[float]
+[[add-links-panel]]
+==== Add a links panel
+
+To add a links panel to your dashboards:
+
+. On the **Dashboards** page, click the dashboard **Title** you want to open. 
+. Click **Add panel > Links**.
+. In the **Create links panel** flyout choose between the panel displaying vertically or horizontally on your dashboard. 
+. Click **Add link**.
+. Specify the following:
+* **Go to** - Dashboard to link to another dashboard, or URL to link to an external website. 
+* **Choose destination** - Use the dropdown to select another dashboard or enter an external URL.
+* **Text** - Enter text for the link, which displays in the panel. 
+* **Options** - When linking to another dashboard use the sliders to use the filters and queries from the original dashboard, use the date range from the original dashboard, or open the dashboard in a new tab. When linking to an external URL use the sliders to open the URL in a new tab, or encode the URL. 
+. Click **Add link**.
+. Click **Save**.
+. Enter the **Title** and **Description**, then click **Save**.
+
+[float]
+[[add-links-panel-from-library]]
+==== Add a links panel from the library
+
+By default links panels are saved to the library. To add a links panel to another dashboard:
+
+. On the **Dashboards** page, click the dashboard **Title** you want to open. 
+. Click **Add from library**.
+. Select the links panel from the **Add from library** flyout.
+. Click **Save**.  
+
+[float]
+[[edit-links-panel]]
+==== Edit links panels
+
+To edit links panels:
+
+. Click image:images/lens_layerActions_8.5.0.png[], then **Edit Links**. 
+. Click image:images/dashboard_controlsEditControl_8.3.0.png[] on the link.
+. Click **Update link**.
+. Click **Save**.
+
+[float]
+[[delete-links-panels]]
+==== Delete links panels
+
+To delete links panels:
+
+. Click image:images/lens_layerActions_8.5.0.png[], then **More**.
+. Click **Delete from dashboard**.
+. Click **Save**.
+
+
 [[create-drilldowns]]
 === Customize interactions with drilldowns