What if one field contains multiple pieces of information (e.g multiple choice and space for “Other")?

You essentially treat each part of the answer as a separate field. Draw separate boxes around each type of data, and define each individually.

In the example given here, you would draw one box around the multiple choice field and define as “select-one” or “select-many,” including all options shown as well as "Other."

Then draw another box around the “Other” field and define it as Text.