For ESA purposes, you must have a policy dealing with, at a minimum, wages, work hours, overtime, stat holidays, vacations, unpaid leaves of all kinds, payment of wages, termination, group termination, equal pay for equal work and payroll records.
You should also have an HR Policy and/or Code of Conduct dealing with workplace issues like discrimination, harassment, conflicts of interest, etc. https://hrinsider.ca/top-10-hr-policies-employers-must-have/ This should help you get a start
OHS-wise, you need a general OHS policy and policies on training, hazard assessment, joint health and safety committees, work refusals, incident investigation and reporting, as well as every hazard/hazardous operation at your workplace from machine servicing, to falls from heights and confined spaces entry.