Obamacare’s web site for small businesses to sign up for health insurance is still non-functioning, but it has a working calculator to find out if you qualify for a tax credit:
https://www.healthcare.gov/shop-calculators-taxcredit/
Be prepared to enter current year projected numbers for: full-time employees; part-time employee hours; total wages; whether the employer will pay 50% or more of the health insurance premiums; and total premiums.
The calculator returns the expected federal tax credit. Businesses that expect to qualify for the tax credit use a different application process than those that don’t. You still have to go through an agent or broker to apply.