When you need to use some type of formatting, such as for a new headings or making text bold, you do this using wiki syntax or the buttons in the edit toolbar above the editing zone.
'''Create an underlined Heading:''' "Equals Signs" create like <nowiki>== References ==</nowiki> creates an H2 heading. <nowiki>=== References ===</nowiki> creates an H3 heading. <nowiki>==== References ====</nowiki> creates an H4 heading. and so on... '''Create an Internal Link:''' <nowiki>[[ Exact Page Title ]]</nowiki> creates a link to that wiki page. <nowiki>[[ Category:Exact Category Title ]]</nowiki> creates a link to that wiki category page. and so on...
See all mediawiki's markup formatting help here: [https://www.mediawiki.org/wiki/Help:Formatting Format Help]