Do you want the first numbered page showing page 1 to be on the 6th page of your document? or

Do you want the first page of your document to show the page number 6? or

Do you want to start numbering on the sixth page of your document with the number 6?

See Sections / Headers and Footers in Microsoft Word 2007-2010 if you are using Word 2007 or later. If an earlier version there is a link at the beginning of the article to a similar article for earlier versions of Word.