docs: update installation instructions for manual setup

Author: mkuthan

README.md

@@ -9,21 +9,7 @@ See [issue tracker](https://github.com/mkuthan/solis-cloud-control/issues) for f
 
 ## Installation
 
-The integration is not currently available in [HACS](https://www.hacs.xyz/). However, you can install it manually by following these steps:
-
-Clone the repository into your Home Assistant filesystem:
-
-```bash
-git clone https://github.com/mkuthan/solis-cloud-control.git
-```
-
-Create a symlink to the `custom_components` directory:
-
-```bash
-ln -s solis-cloud-control/custom_components custom_components/solis_cloud_control
-```
-
-Restart Home Assistant and search for "Solis Cloud Control" in the integrations page.
+The integration is not currently available in [HACS](https://www.hacs.xyz/). However, you can install it manually by adding [custom repository](https://www.hacs.xyz/docs/faq/custom_repositories/).
 
 > [!TIP]
 > For updates on HACS availability, see [issue #7](https://github.com/mkuthan/solis-cloud-control/issues/7).