Updated error docs and include aka.ms link

Documentation/guides/messages/xa5207.md

@@ -7,14 +7,33 @@ ms.date: 06/26/2019
 
 ## Example messages
 
-```
+```dotnetcli
 XA5207: Could not find android.jar for API Level 28. This means the Android SDK platform for API Level 28 is not installed. Either install it in the Android SDK Manager (Tools > Android > Android SDK Manager...), or change your Xamarin.Android project to target an API version that is installed.
 ```
 
 ## Issue
 
-In order to build a project, the Android SDK Platform matching the target API level must be installed. 
+In order to build a project, the Android SDK Platform matching the target API level must be installed.
 
 ## Solution
 
-Use the Android SDK Manager to install the Android SDK Platform for the desired API level.
+Use the Android SDK Manager (Tools > Android > Android SDK Manager...) to install the Android SDK Platform for the desired API level. Alternatively you can install the missing API level by running the following from a terminal or command prompt
+
+`dotnet build -t:InstallAndroidDependencies -f net8.0-android -p:AndroidSdkDirectory=<path to sdk directory>`
+
+Part of the new .net android system is when upgrading projects you will automatically be
+upgraded to the latest API level. For example net7.0-android allowed you to target API 33,
+but net8.0-android will automatically target API 34. If you want to keep your current
+target API level you will need to add the 'uses-sdk' `android:targetSdkVersion` to your `AndroidManifest.xml` file.
+
+```xml
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    android:versionCode="1"
+    android:versionName="1.0"
+    package="com.companyname.myapp">
+    <uses-sdk android:targetSdkVersion="33">
+    <application android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" />
+</manifest>
+```
+
+You might then need to run the `InstallAndroidDependencies` target as mentioned above to ensure that the required API level is installed.

src/Xamarin.Android.Build.Tasks/Properties/Resources.resx

@@ -867,7 +867,7 @@ Remove the '{0}' reference from your project and add the '{1}' NuGet package ins
 {0} - The missing tool name</comment>
   </data>
   <data name="XA5207" xml:space="preserve">
-    <value>Could not find android.jar for API level {0}. This means the Android SDK platform for API level {0} is not installed. {2} ({1} missing.)</value>
+    <value>Could not find android.jar for API level {0}. This means the Android SDK platform for API level {0} is not installed. {2} ({1} missing.) See https://aka.ms/xa5207 for more details.</value>
     <comment>The following are literal names and should not be translated: android.jar
 {0} - The API level name
 {1} - The expected path of the android.jar file