Which broken links? and remember to post version number :)

Are you just looking for the help page?

If you use the manual https://b2evolution.net/man/disp-help you will see there is a 'disp' page.

Look in the skin_fallback or your skin if you have an override look in your skin, and look for the file in this case _help.disp.php

There are some broken links in the above Section, I want to change the Url.

This is displayed by a widget, which in turn displays a content block, which you can edit in the back-office.

See "Help content" here: https://b2evolution.net/man/content-blocks-view

I did not create any Content Block, This is the default Content block that is getting displayed, I want to edit the default one.

Yes, you can edit the default content block from that screen: https://b2evolution.net/man/content-blocks-view