On the "Home" ribbon at the top of screen, in the STYLES section click on the arrow pointing to the lower right-hand positon (the Styles menu will appear). In the Styles menu in the lower right-hand side click on "Options" (the Stles Pane Options menu will appear). On the "Select styles to show:" drop-down menu, select "All Styles". Optionally, you can also select "Alphabetical" from the "Select how list is sorted". Click OK. Scroll down the list to the Heading 1-9 styles and select your desired style.