Creating password protected section on our site

Our website [login to view URL] has a section that I would like to have password protected and I host it on Yahoo Small Business server and I am having a difficult time understanding how to set it up. I would like to have a setup where our clients can be provided login and password information and then be able to click on the Toolkit link and login to gain access to specific items we want to only allow them access to. The person interested in this project will be provided all access to our account so they can go in and read up on how to do it with yahoosmallbusiness or they can offer a solution on their own. The site is new and this is the only outstanding issue. Please look at the site and let me know what you would need to proceed.