When I first started learning Korean, of course I chose to start with the basics: the ABCs.
I looked through a lot of resources online and found a lot of helpful sites and videos. The one YT channel that's really helped me learn to read Hangul letters (consonants, vowels, double consonants and dipthongs) was sweetandtasty's channel on YT. In fact, I learned it all in a weekend. I also like the worksheets she provides in AnyongKorea.com. You can print them out and practice writing Hangul while watching the video.