Hi adamsoa,
It's time you learnt to use paragraph Styles. When you apply a given paragraph Style to a paragraph, simply changing that Style's definition updates all paragraphs formatted with that Style to the new definition. That defintion includes all of the attributes you find via the Paragraph formatting dialogue. See:
http://office.microsoft.com/en-us/wo...010230882.aspx
http://office.microsoft.com/en-us/wo...001187614.aspx
http://www.addbalance.com/usersguide/styles.htm
http://www.shaunakelly.com/word/styl...sonstyles.html
That said, you should be able to apply the indenting to all paragraphs in the document via Ctrl-A (to select the entire document), then changing the paragraph indents.