DOCS: VENV step missing from develop install instruction

**Describe the issue**
A clear and concise description of what documentation is missing or incorrect.

The developer step should be self-contained. However, the step to create a VENV is missing.


**Where to find**
Where to find the error or where documentation should be:
(website/github/docstrings/etc.)
- Make a list

**Additional info**
Add any other information here.
