Welcome back!! It seems like it would be hard to beat the step by step instruction you get here.

As far as remembering what you've learned - repetition is the key. As the saying goes...if you don't use it, you lose it. If you want to remember something and have it ready at command, add it to your practice routine to run through it at least once. Once you've committed it to memory, it will retain longer. If you commit it to long term memory and it starts to fade, it's also easier to bring it back. But my experience has been that if you want it in long term memory, you have to repeat playing it over and over and over and over...

So, each time you sit down to learn something new on your guitar, make sure you review what you've learned previously and run through any licks or progressions you want to retain.