Website Training:
https://linuxjourney.com/
https://training.linuxfoundation.org/free-linux-training
http://www.tecmint.com/free-online-linux-learning-guide-for-beginners/

YouTube Introduction Training:
(it is better to just do it rather than watch the video)
https://www.youtube.com/watch?v=9t_gJWC32zk

Free eBooks:
http://www.rickyadams.com/wp/wp-content/uploads/2017/05/linuxfun.pdf
http://www.rickyadams.com/wp/wp-content/uploads/2017/05/Introduction-to-Linux-Hands-On.pdf
http://www.rickyadams.com/wp/wp-content/uploads/2017/05/Linux-Advanced-Administration.pdf

Online Resources:
http://www.rickyadams.com/wp/index.php/linux/
http://www.rickyadams.com/wp/?s=linux
https://en.wikibooks.org/wiki/LPI_Linux_Certification
http://linuxreviews.org/