Add HOWTO for Python VIrtual Environment.

docs/howto_guides/How-To-Guides.md

@@ -8,4 +8,5 @@
 01. [How do I create a model library to save compilation time?](/trick/documentation/building_a_simulation/Trickified-Project-Libraries)
 01. [How do I use inherited templates in the input file?](How-To-Use-Inherited-Templates)
 01. [How to Dump a Core-file on MacOS](How-to-dump-core-file-on-MacOS)
-01. [How to Containerize Trick with Docker](How-To-Containerize-Trick-with-Docker)
+01. [How to Containerize Trick with Docker](How-To-Containerize-Trick-with-Docker)
+01. [How to Setup a Virtual Python Environment](How-To-Python-Virtual-Environment)

docs/howto_guides/How-To-Python-Virtual-Environment.md

@@ -0,0 +1,58 @@
+## HOWTO Setup a Python Virtual Environment
+
+
+### Creating a Virtual Environment
+
+The following command creates a virtual Python environment:
+
+```% python3 -m venv <path-of-virtual-environment>```
+
+This command runs the ```venv``` module, to create a virtual environment. The 
+directory specified by ```<path-of-virtual-environment>``` is created to store
+the resources of the environment. It contains scripts to activate, deactivate,
+and otherwise configure the environment. It also provides a place to install Python
+modules for that particular environment. One can create multiple virtual environments,
+each with different resources.
+	
+For example, the following will create a Python virtual environment called ```myVenv```
+in your home directory.
+	
+```% python3 -m venv ~/myVenv```
+
+### Activating the Virtual Environment
+
+To activate the virtual environment, execute the following:
+
+```
+% source myVenv/bin/activate
+```
+
+Note that the name of virtual environment is added to the command prompt.
+
+### Installing Python Modules Into Your Virtual Environment
+
+Use the following command to install Python modules into the virtual environment:
+
+```
+(myVenv) % python3 -m pip install <package-name>
+```
+
+For example, the Trick test suite, which uses TrickOps which requires PyYAML.
+This Python module would be installed as follows:
+
+```
+(myVenv) % python3 -m pip install PyYAML
+```
+
+Every time ```myVenv``` is activated, the PyYAML module will be available.
+
+
+### Deactivating the venv Shell
+To deactivate the venv shell, execute the following:
+
+```(myVenv) % deactivate```
+
+
+The above should get you going. If you need more details, the following tutorial is pretty good.
+[RealPython Tutorial](https://realpython.com/python-virtual-environments-a-primer/).
+