Build Tesseract from source video:
https://www.youtube.com/watch?v=veJt3U44yqc
GitHub repository link:
https://github.com/astutejoe/tesseract_tutorial
Training command:
TESSDATA_PREFIX=../tesseract/tessdata make training MODEL_NAME=Apex START_MODEL=
eng TESSDATA=../tesseract/tessdata MAX_ITERATIONS=10000
Correction: I believe the box file contains the bounding box (OBB) coordinates of the character within the image