Add comments in code for better understanding

Right now there are minimal comments in the project. For someone to easily understand the repository, it is important to add comments in the code for a given logic.

The issue names no files, entry points, or tests. Start by inspecting the repository to identify logic that currently lacks comments, then clarify which areas should be documented and what level of explanation is expected. Done should mean the agreed code paths have useful comments without unnecessary duplication.

Written by the indexing model from the issue text.