Update docs for the load command

[stkerr]

Description

Update the docs with more info about what needs to be in the portfolio files

How has this been tested?

• Please describe the tests that you ran to verify your changes.
• Provide instructions so we can reproduce.
• Please also list any relevant details for your test configuration.

Checklist:

• Update our Hugo documentation following these guidelines.
• Update our tests following these guidelines.
• Make sure you are following our CONTRIBUTING guidelines.
• If a feature was added make sure to add it to the corresponding scripts file.

Others

• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• My code passes all the checks pylint, flake8, black, ... To speed up development you should run pre-commit install.
• New and existing unit tests pass locally with my changes. You can test this locally using pytest tests/....

[stkerr]

@DidierRLopes @jmaslek can you review and merge this PR? Thanks!