DOCATT-6350 - Installation note in landing page

com.unity.cinemachine/Documentation~/index.md

@@ -2,6 +2,9 @@
 
 ![Unity Cinemachine](images/CinemachineSplash.png)
 
+>[!NOTE]
+>To use the Cinemachine package, you must install it separately from the Unity Editor. For detailed information about package requirements and installation instructions, refer to [Installation](InstallationAndUpgrade.md).
+
 Cinemachine is a suite of modules for controlling  the Unity camera. Cinemachine solves the complex mathematics and logic of tracking targets, composing, blending, and cutting between shots. It is designed to significantly reduce the number of time-consuming manual manipulations and script revisions that take place during development.
 
 The procedural nature of these modules makes Cinemachine robust and forgiving. When you make adjustments - for example, change an animation, vehicle speed, terrain, or other GameObjects in your Scene - Cinemachine dynamically adjusts its behavior to make the best shot. There is no need, for example, to re-write camera scripts just because a character turns left instead of right.