You must understand that BookLibary Component is not translator.
You can change the name of elements in what language you need with help language manager of BookLibary Component
or with language manager of Joomla
and a switcher built in, now you can create a site in different languages without external components like was before.
One thing remained unchanged if you want to create a website in two languages, you have to create content in two languages. Just because you create a multilingual Joomla! website doesn’t mean it will translate your content for you. So first create your content in both (or all) languages!
Configuration Joomla Multilanguage site is divided into few steps.
Additional language installation.
Configure Language Filter and Language Switcher.
Create Menu for every language.
Create Language Switcher module.
Create menu items for languages
or look on video