Update README.md

README.md

@@ -14,3 +14,6 @@ The easiest way to install this component is by clicking the badge below, which
 [![Open your Home Assistant instance and open a repository inside the Home Assistant Community Store.](https://my.home-assistant.io/badges/hacs_repository.svg)](https://my.home-assistant.io/redirect/hacs_repository/?category=Integration&owner=LarsK1&repository=hass_solvis_control)
 
 You can also add the integration manually by copying `custom_components/solvis_control` into `<HASS config directory>/custom_components`
+
+# Preparation:
+For using this integration you are required to enable the Modbus Protocol on your Solvis Device. Please follow this guide: https://solvis-files.s3.eu-central-1.amazonaws.com/downloads-fk/regelung/sc-3/SC-3_ModBus_Schnittstellenbeschreibung.pdf