Try this one https://www.vulnhub.com
This site isn't really tutorials but vulnerable VM's with walkthroughts of ways people were able to root the box.
Very nice for some hands on learning. they do have links for some training material in there resources tho .
https://www.vulnhub.com/resources/There are tons of sites full of tutorials tho , just google pentesting tutorials , hacking tutorials , learn hacking and so on .