Add documentation to data access functions

[verovaleros]

Description

To add the new feature that would allow AIP read data from multiple sensors it's paramount to understand how models read, process and handle data. This PR introduces documentation changes in the data access functions, in preparation to implement the feature we need.

Type of change

• This is a documentation update

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings