how to memorize openings

Chessable is also good. You can use it to create your own "courses", which you can use to store your own repertoire, together with notes (which you write yourself) to remind you of the principles behind the moves you have chosen. 

Chessable will also then test you on your lines, using spaced repetition.

Of course you can use other people's courses - some of which cost money, others are free - but I believe composing your own is the best way.

I liked the previous Homer better.

I'm disappointed in your response, Mr Spongey - I would have expected you to post more links to back up your opinion here  

DOH!

https://chessmood.com/blog/how-to-memorize-chess-openings-variations The best article and the best recommendations from GM's. Hurry up and read it!