PhD in OB vs. Psych: https://ideas.wharton.upenn.edu/wp-content/uploads/2018/11/So-you%E2%80%99re-interested-in-a-PhD.pdf
I highly recommend checking out the Business PhD Wiki, which contains several resources, like examples of personal statements and CVs of successful PhD applicants: https://businessphdwiki.com/doku.php
If you're wanting to learn more about business academia, consider applying to the Summit program, which is a fully-funded, two-day program that introduces undergraduates to the field of business academia: https://doctoral.wharton.upenn.edu/summit/
Prof. Jess Calarco's book: A Field Guide to Grad School: Uncovering the Hidden Curriculum. https://press.princeton.edu/books/paperback/9780691201092/a-field-guide-to-grad-school
Science's Letters to Young Scientists series: https://www.science.org/topic/careers-overline/letters-young-scientists
Prof. Zeke Hernandez's article on work/life balance as an academic: https://hbsp.harvard.edu/inspiring-minds/yes-you-can-succeed-in-academia-and-still-have-a-personal-life