If you don’t have any posts in the Trash, then there won’t be a link to go and see them. What would be the point of displaying a link to an empty page, after all?
The link to Trashed posts appears on the All Posts screen at the top, right alongside All | Published | Drafts and so forth. If you want to see it appear, make a new post, and then trash that post so that you actually have something in the trash.
Also, WordPress 3.8 is over 3 years old now. Seriously, just click the update button.