Under "Rows to repeat at top" click on the arrow and then select your rows.
I.e., if you want the first three rows to be header for all other sheets, it
will put in $1:$3.
LoriM has made a good suugestion if you want to print the headers on each
page.
If by "pages" you mean "worksheets" and you don't mean when printing, you can
select all the sheets(r-click and "select all sheets") and type your
headers/titles on one sheet and they will be entered on all selected sheets.