Here are high quality scans of traditional Boy Scout training material for the International Morse Code or, in BSA’s classic terminology, the service code.
This link takes you to my YouTube video of BSA’s LP training record set.

Here are the LP liner notes and instructions from an official BSA Signal Kit:
BSA Raybrun Morse Code Liner Notes
BSA Signal Kit Literature optimized
Here you’ll find my one-page practice chart of letters in the recommended study groups: