Add step-by-step instructions for opening ROOT files in the viewer

src/docs/getting-started/quickstart.mdx

@@ -66,25 +66,50 @@ Later on, we will com back to these detector repositories.
 
 ## Step 3: Looking at the geometry
 
-Before moving on to part 1, let's generate the geometry in a root file:
+Before moving on to part 1, let's generate the geometry in a ROOT file:
 
+**Note: if you want to skip this, you can [click here to view the latest detector from the athena repository](https://eic.phy.anl.gov/geoviewer/index.htm?file=https://eicweb.phy.anl.gov/api/v4/projects/473/jobs/artifacts/master/raw/geo/detector_geo_full.root?job=report&item=default;1&opt=clipxyz;transp30;zoom75;ROTY290;ROTZ350;trz0;trr0;ctrl;all&).**
+
+For this example we will generate a geometry ROOT file (called `detector_geometry.root`),
+copy this file to your local computer and open it with our web viewer.
+To generate the geometry file, please execute the following commands:
 
 ```bash
 cd athena
 source /opt/detector/setup.sh
 dd_web_display --export athena.xml
 ```
+(Note: the `source /opt/detector/setup.sh` command adds the Athena detector plugins that ship
+with the jug_xl container to your environment.)
 
-This will generate the file `detector_geometry.root`, which you should copy to your local machine.
-Then open the [web viewer](https://eic.phy.anl.gov/geoviewer/), click on the `...` and open the local root file.
+Please copy this file to your local computer (using `scp`) if working on a remote system.
+Then open the [web viewer](https://eic.phy.anl.gov/geoviewer/), and click on the `...` and
+open the local ROOT file from your hard drive.
 
-Or if you want to skip this just 
-[click here to view the latest detector](https://eic.phy.anl.gov/geoviewer/index.htm?file=https://eicweb.phy.anl.gov/api/v4/projects/473/jobs/artifacts/master/raw/geo/detector_geo_full.root?job=report&item=default;1&opt=clipxyz;transp30;zoom75;ROTY290;ROTZ350;trz0;trr0;ctrl;all&).
+![viewer_step1](../quickstart_viewer_1.png)
 
-(Note: the `source /opt/detector/setup.sh` command adds the Athena detector plugins that ship
-with the jug_xl container to your environment.)
+This will populate the sidebar with the objects in the ROOT file. Right click on "default"
+and then click on "Draw" in the top-level menu (you don't have to select any specific
+draw-options in the draw submenu, you only need to click on "Draw" itself).
+
+![viewer_step1](../quickstart_viewer_2.png)
 
+Now you will see the detector geometry in the main viewer window. In order to modify the
+view you can:
+ * Right-click and drag to move the view around (or two-finger drag on a mobile device).
+ * Left-click and drag to rotate the view (or one-finger drag on a mobile device).
+ * Use your mouse wheel to zoom in and out (or pinch on a mobile device).
+ * Click on the blue square on in the bottom left of the canvas to open the controls. Here
+ you can change settings such as cut-outs (clipping, try selecting all of 'X', 'Y', and 'Z'), and transparency (under "appearance").
 
+![viewer_step1](../quickstart_viewer_3.png)
 
+Finally, you can browse and display the subgeometries in the file.
+Double-click on "default" and then "world_volume" to expand the list of objects. You can
+also expand each of the sub-geometries in their components. 
+To display one of the sub-geometries, right-click on the component you want to view and
+select "Draw".
 
+![viewer_step1](../quickstart_viewer_4.png)
 
+That's all. You should now be ready to continue with Part 1 of the tutorial.