add windows/Mac source install instructions

Installation.md

@@ -123,6 +123,46 @@ $ docker run --entrypoint /opt/kcc/kcc-c2p.py --rm -v "$(pwd):/app" ghcr.io/ciro
 
 ### INSTALL FROM SOURCES
 
+Easiest to use [GitHub Desktop](https://desktop.github.com) to clone the KCC repo. From GitHub Desktop, open a Command Prompt/Terminal Window in the repo.
+
+We recommend using [virtual environments](https://docs.python.org/3/tutorial/venv.html) to manage dependencies. A code editor like [VS Code](https://code.visualstudio.com) will automatically activate virtual environments. 
+
+#### Windows
+
+One time setup: Setup a virtual environment and run:
+```
+python -m venv venv
+venv\Scripts\activate.bat
+pip install -r requirements.txt
+python kcc.py
+```
+
+Every time you close Command Prompt, you will need to re-activate the virtual environment and re-run:
+
+```
+venv\Scripts\activate.bat
+python kcc.py
+```
+
+#### Mac
+
+One time setup: Setup a virtual environment and run:
+```
+python3 -m venv venv
+source venv/bin/activate
+pip install -r requirements.txt
+python kcc.py
+```
+
+Every time you close Command Prompt, you will need to reactivate the virtual environment and re-run:
+
+```
+source venv/bin/activate
+python kcc.py
+```
+
+#### Linux
+
 _Originally posted by @hhtien1408 in https://github.com/ciromattia/kcc/issues/438#issuecomment-1281159452_
 
 ```bash