How do I expense a training course as a business expense on my return for a business partnership registered after the course was already taken. Business hasnt made revenu

How do I expense a training course as a business expense on my return for a business partnership registered after the course was already taken. Course taken Dec 2021, Business partnership officially registered Feb 2022. Business hasn't made revenue yet as I'm still in the process of ordering stock. But expenses have occurred. I I should add I have already submitted my return, so this will be a refile. Thank you