Added 'how to run' docs

README.MD

@@ -15,6 +15,10 @@ macOS/Linux:
 `source <environment_name>/bin/activate`
 
 ## Run script
+First ensure that all requirements are installed: `pip install -r requirements.txt`
+
+Then run the command below to create the potree structure.
+
 
 ```zsh
 python lasConverter.py <input_directory> <output_directory>