The best way I have found is to just jump in and try the security tools. On networks you own and have permission for of course! DO NOT DO THESE on your company networks without permission and some understanding/experience with the tools.
I have gained massive experience by trying and failing on my own lab networks.
Back in the day I had to have 14 computers, a KVM switch, my own routers and switches. Now I can use a virtual machine (Oracle's Virtual Box, VMWare Player, etc) which are free to simulate machines. No longer do I have to have the noisy basement, but a streamlined computer dedicated to providing the lab environment I need.
You will seriously have more learning experiences if you do it yourself and do the research into setting it up and struggling versus some nicely laid out training program. Not that I am against structured training, but that should not be your sole desire. Insecure.org has lots of free/trial programs you can download. Download some Linux ISO's. Download KALI Linux. Use any free tools you can get your hands on and try/fail/succeed at as many things you can.