I just modified the .htaccess file in the first part of the answer for my Wordpress site to redirect http:// to https://. I didn't need to modify the index page and it worked fine for me without it. Thanks to the author of that as it completed my quest for a secure certificate migration.
My complete file .htaccess file looked like this for me. I suggest making a local copy as I broke my site a few times before I found the right answer for me here:
#RewriteCond %{HTTP_HOST} ^yoursite\.com [NC]
#RewriteRule (.*) http://www.yoursite.com/$1 [R=301,L]
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress
Options +FollowSymlinks
RewriteCond %{SERVER_PORT} 80
RewriteRule ^(.*)$ https://www.yoursite.com/$1 [R,L]