Spouse Follow To Join, what's next?

[gabrielg74]

Hello, I was approved my immigrant visa, and I was told my wife was already included in the processing. She appears as "Follow To Join" in the Department of State website, but there is no option to pay any fees nor fill the DS-260 for her ("Not Applicable" appears in the Applicant Information Summary for her).
What should I do? Or what are the requirements to continue her processing?

Your help will be greatly appreciated.

Thanks,

Gabriel G.