Vulnhub has hundreds of virtual machine images you can download and practice with, such as metasploitable. Hack the box is great. If you want to read a blog post describing how to get admin or root on a box, google boxname walkthrough with vulnhub or hack the box in the search as well. Ippsecs's 90+ youtube videos are excellent. Check out metasploit minute videos. I also heard pentestlabs is good. Good luck!