How to add login fields to Membership page / for existing subscribers to the page?

This is an URGENT REQUEST - I have to show it to client on Mon.:

• I am using the Membership plugin.
• I am creating the username and passwords for their investors.
• I have a level established just for investors.
• The investor page is a content protected page.
• I want to restrict certain PDFs and require a login (username/pswd) to view and download them.

How do they login in on this page to see it using the username and password I have already set up for them? There is no login area/fields.

How do I add this login info around the content that I need to be protected.

Here is the url to the page: