[docs] - Upstream changes for assets [CON-36] (#8175)

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* Add screenshot and update copy

* Fix anchor link

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docs/content/concepts/assets/software-defined-assets.mdx

@@ -114,27 +114,70 @@ If you want Dagit to contain both an asset group and a set of [jobs](/concepts/o
 
 ### Viewing assets in Dagit
 
-Clicking on "Assets", in the right section of Dagit's top navigation pane, takes you to the Asset Catalog, which shows a list of all your assets.
+- [All assets](#all-assets)
+- [Details for an asset](#asset-details)
+- [Dependency graph](#dependency-graph)
+- [Upstream changes](#upstream-changed-indicator)
+
+#### All assets
+
+To view a list of all your assets, click **Assets** in the top-right corner of the page. This opens the Asset Catalog:
 
 <img
 alt="Asset Catalog"
 src="/images/concepts/assets/software-defined-assets/catalog.png"
 />
 
-Clicking on the name of one of these assets will take you to the Asset Details Page for that asset.
+#### Asset details
+
+View the Asset Details page for an asset by clicking on its name:
 
 <img
 alt="Asset Details"
 src="/images/concepts/assets/software-defined-assets/details.png"
 />
 
-You can view a graph of all the assets with their dependencies by clicking the graph icon to the upper-left of the Asset Catalog, or by clicking "View in Graph" on any of the assets.
+#### Dependency graph
+
+To view a graph of all assets and their dependencies, you can:
+
+- Click the graph icon to the upper-left of the Asset Catalog
+- Click **View in Graph** on any asset
 
 <img
 alt="Asset Graph"
 src="/images/concepts/assets/software-defined-assets/graph.png"
 />
 
+#### Upstream changed indicator
+
+On occasion, you might see an **upstream changed** indicator on an asset in the dependency graph or on the Asset Details page:
+
+<img
+alt="Asset Graph with an upstream changed indicator"
+src="/images/concepts/assets/software-defined-assets/upstream-changed.png"
+/>
+
+This occurs when a downstream asset's last materialization took place **earlier than the asset it depends on.** Dagit displays this alert to notify you that the contents of an asset may be stale. For example:
+
+- `comments` is upstream of `comment_stories`
+- `comment_stories` depends on `comments`
+- `comment_stories` was last materialized on February 25 at **5:30PM**
+- `comments` was last materialized on February 25 at **7:05PM**
+
+In this case, the contents of `comment_stories` may be outdated, as the most recent data from `comments` wasn't used to compute them.
+
+You can resolve this issue by re-materializing the downstream asset. This will re-compute the contents with the most recent data/changes to its upstream dependency.
+
+<Note>
+  Currently, the <strong>upstream changed</strong> indicator won't display in
+  the following scenarios:
+  <ul>
+    <li>The upstream asset is in another asset group or job</li>
+    <li>The assets are partitioned</li>
+  </ul>
+</Note>
+
 ### Materializing assets in Dagit
 
 There are a couple ways in Dagit to launch a run that materializes assets: