Learning Regular Expressions will make you feel like a super hero...
I'm not familiar with Apache rewrite, but one you understand the regex, you'll be able to add what you need to put in there.
On the line:RewriteRule ^index\.php$ - [L]
• The ^ means the start of a string
• The \. Is escaping the . Because . (period) matches any character in regex. You want it to Match just a period.
• The $ means the end of a string
So, the regex ^index\.php$ Matches index.php
Those REWRITE_COND values aren't filled out. Could be /preanutbutter for example.
The rule would replace /index.php with /peanutbutter as the URL.
I like to use
regexr.com for testing and learning.