If like this user you already have the numbers inserted select the page number field.
Go to the Insert menu and the Page Numbers option.
There should be a few drop-down boxes and a check box for "Show number on first page" - just uncheck it and you should be good to go.

This menu also has the setting to adjust the placement of the page numbers on the page for "inside" and "outside" alignments, which is another really common question I hear a lot.