Hi!
Here are some links that can help you with the understanding of Apprenticeship Training Tax Credit:
https://www.fin.gov.on.ca/en/credit/attc/
https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/corporations/provincial-territorial-corporation-tax/ontario-provincial-corporation-tax/ontario-apprenticeship-training-tax-credit.html
Thank you!