Lightning Community - Landing Page/Home Page

Here is what I did in my developer edition sandbox based on what you provided in the comments and question:

1. Created a community and selected template as Napili.
2. When you create community, It creates a site also go to site(Settings->Develop->Sites)
3. Here add the custom VF page you built(Site Visualforce Pages section).
4. Active Site Homepage should be "CommunitiesLanding"

5. Add a URL redirect for the site as something like below(replace 'SimplePage' with your Disclaimer page):

   

6. On your disclaimer page, wherever you want to display community login url, use something like this:

   <apex:outputLink value="/CommunitiesLogin"> Community Login</apex:outputLink>
   

so with all this what will happen is :

1. User enters url for the site in the browser.
2. User is shown the SimplePage because we set the URL redirect for the site to this page in the above screenshot.
3. This page shows a hyperlink and clicking on it will take user to community login page.
4. Entering credentials will take user to Community home page(Because Active Site Home page is set to "CommunitiesLanding").

Here on step 2, looks like you want to show disclaimer info and other stuff.