Could not install

I’ve used this plugin before, but when trying to install it on a site using the Agile theme, it seems to just stop at…

Installing Plugin: FAQ Manager 1.331

Downloading install package from https://downloads.wordpress.org/plugin/wordpress-faq-manager.1.331.zip…

If I go into my Plugins page, I can activate it, but there is no FAQ option anywhere in my sidebar once it’s activated.

Have tried installing three times, but with no joy.

https://wordpress.org/plugins/wordpress-faq-manager/