Recursively change group ownership of the wp-content folder, keeping your ownership of the folder:
chown YOURUSERNAME:www-data -R /var/www/html/wp-content/*
Note: YOURUSERNAME is the Linux user you created in step E.
Recursively enable write permissions for the group on wp-content subfolders and also for files in the folder and subfolders:
cd /var/www/html/wp-content
find . -type d -exec chmod -R 775 {} \;
find . -type f -exec chmod -R 664 {} \;