I'd suggest hiring a firm to provide the documents. A POP doesn't cost much, and then you know the paperwork is right.
After that, it's easy. Just have to make sure that payroll keeps the pre-tax part separate from the after-tax part of employees' pay.
If possible, an automatic enrollment is easier (employees become participants whenever they are eligible for the health coverage). In this mode, employees must be offered the opportunity to waive participation.