Create the hyperlink that'll take you to that text or object.
Now, go to the part of the post you'd like to have the hyperlink in. You'll need to add a typical hyperlink HTML markup, but in the part where you'd typically include a URL, you'll include the pound symbol (#) then the name of the object you're linking to. Here's what it looks like:
<a href="#INSERT_YOUR_OBJECT_NAME_HERE">Click here to see the content below.</a>