In Word, look across the top, find the word "Help", click on it.
Select "Microsoft Office Word Help".
(Alternatively, with Word as the active application, press the "F1" key")
In the "Search For" area under assistance - type in your query.. In this
case, type in (sans the quotes):
"double space"
(If you look through the answers, it will point you to "Format -->
Paragraph" and "Indents and Spacing" and "Spacing" Section...)