Can you help me with installing simple sitemaps for multisite?

I am following directions on this page:
https://premium.wpmudev.org/project/sitemaps-and-seo-wordpress-mu-style/#usage

I have done all the steps up to #4. I open up my .htaccess file and it looks like this:

# BEGIN WordPress
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]

# add a trailing slash to /wp-admin
RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) $2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]

# END WordPress

Nowhere do I see a line under the line that handles uploaded files to upload this line:

RewriteRule ^(.*/)?sitemap.xml wp-content/sitemap.php [L]

Thanks in advance! Linda

Thanks in advance.