Customize a template in Wordpress

I need help setting up my Wordpress website with (1) a customized theme, (2) setup site with https using my SSL certificate, and (3) a plugin for a membership directory. I am trying to expand my basic skills and learn how to build sites; as such, I volunteered to put together a website for the 50th reunion of the USMMA who graduated in 1965. I have built this site twice and had the above features implemented, but then had the website fall completely apart when I tried to customize the code. The goal of the site is to have a place where members can make contact with each other (by providing a member directory), make blog posts, upload and view picture galleries, and provide information about the 50th union that will take place in Sept 2015. 1. I have purchased 2 themes on [login to view URL] for a Wordpress site that I need help customizing. I can use [login to view URL] or [login to view URL] 2. The site is hosted on GoDaddy and the SSL was also purchased from GoDaddy. 3. I have purchased a membership-directory plug-in, but I am not sure if it is compatible with my theme; or if I need to use it at all (can I just use what Wordpress provides)? Can someone help me put together this Wordpress site, so I can put my content and pics back in?