In order to make your affiliate program works, you need to share the affiliate registration form to proper people to get them sign up as your affiliates.
It depends on your targeted affiliates (professionall affiliate, influencers on social media or even your own customers, etc.) to choose where to share the form. Take a look at this article 8 TIPS to share your Affiliate programs to get more idea.
You can also make your affiliate program more visible by adding it on your shop menu by following the next document about: Publish affiliate form on shop menu.