HR Policies for Small Construction Companies: What Acts Should I Follow as We Grow?

I am working in a small construction company with around 18 employees in the office. I need to know which acts to follow here. In the future, there may be an increase in manpower, so I need to create some HR policies for the staff and workers. Can anybody please guide me?

I am attaching some startup policies, rules, and regulations. I hope this will help you.

Regards