wont fully install with latest version of wordpress

[guessimanoob]

Im trying to install the latest version of this plugin with thelatest version of wordpress. Even after following these steps

" Featurific for Wordpress is almost ready. To complete installation, Featurific for Wordpress needs access to your main template file.
Temporarily modify your theme's file permissions and reinstall
Change the file permissions on your current theme's files to be world-writable (chmod 666 should suffice)
Using an FTP client (easy)
Using the command line (harder, requires shell access)
Deactivate and re-activate Featurific for Wordpress, and installation will complete successfully if the main template file is in fact world-writable.
Optional: If desired, revert your permissions back to normal. (chmod 644 for files, chmod 755 for directories)
Manually insert the Featurific code Instead of modifying your permissions so that Featurific can install itself into your theme automatically, you have the option of installing Featurific manually. For instructions on how to do so, visit the Featurific website.
To get rid of this status message, either complete the steps listed above or disable the Featurific for Wordpress plugin."

The only thing I could find was one that suggested it was because the site had large amounts of post with no solution as of then, but that was over 2 years ago surely there is a fix by now right? Or maybe there is another solution. Also i was going to try and install it manually but i could not find instructions for how to do so on wordpress only for an html site. I would love to use this plugin if someone could help me get it going.