Landing / Static HTML page

I want to use static HTML for a landing page on a WordPress site. For example:

• example.com – WordPress already running in root folder
• landingPage.example.com – I purchased this static landing page using
  ThemeForest

Just name the landing page file index.html and place it (and any assets) in the root directory, then add this to your .htaccess (assuming you’re using Apache):

DirectoryIndex index.html index.php

When accessing http://example.com, Apache will serve index.html. WordPress will scoop up all other requests with it’s rewrite rules.