@Aubrey.Raile hey there, it's my understanding typically people use the one by Ellen Cassidy (the green one), but I can't guarantee I'm correct. If you find out that the Cassidy one is the book you wish to use, she's currently in the final stages of creating her LR focused online course. I'm not sure if it is open for everyone yet, but as someone who purchased the book, I have been getting emails about her course opening in beta, so it may be something for you to look into more!