Need Clear Guidance on Math Delimiters and Grouping

When typing math expressions, it is unclear what is included within the AutoCorrect code portion of the expression. Is it the space character or something else that determines what is associated with the AutoCorrect item? This probably requires documentation on this behavior.
• Users are confused about:
• when to use parentheses vs spaces,
• how Word determines grouping (e.g., what belongs under a square root),
• how to explicitly delimit expressions.
• No clear explanation of:
• how expressions are terminated,
• when a structure (e.g., sqrt, superscript, vector) ends.
• Pressing Enter may:
• exit the math editor,
• create a new line within the equation,
• start a matrix or aligned structure.

Start by investigating the math AutoCorrect and grouping behavior described in the issue, including spaces, parentheses, explicit delimiters, structure boundaries, and Enter. Document how expressions are terminated, what belongs to structures such as square roots and superscripts, and how Enter behaves in each context. Done means users have clear guidance for all listed cases.

Written by the indexing model from the issue text.