Start with statutory

Health & safety policy (if you have more than five employees).
Disciplinary and dismissal policies.
Grievance policy.
Full list as per DfE guidelines here www.gov.uk/.../statutory-policies-for-schools-and-academy-trusts
Not everything on the list is HR specific but plenty is

Then think about what else you require. (If not already on above list)
Safer recruitment
Code of conduct
Bullying and harassment
Managing attendance
Leave of absence
Flexible working
Maternity
And so on

Does the school recognise trade unions? If so, you should consult with unions first. Send them your policies and ask them to comment. Consider their comments and respond. You should also make them available to employees and ask for their comments also. Put in deadlines.

Perhaps hold forums to respond to comments.

You do not have to make changes but demonstrate you have listened and justify why you’re not changing it to align with their view.

Make the final versions available on your intranet/staff rooms etc.

In reply to Sasha:

And put them through board of governors also for approval

There are some statutory policies that you need to have in place, as Sasha set out. But another starting point is your current practice - just because a policy isn't written down, doesn't mean it doesn't exist. Find out what has been used as guidance in the past, what practical examples or precedents exist, and that might give you a place to build from.

Do you have access to The Key? Some excellent resources and guidance.