You can enable the ESL+30 mins in via https://www.certmetrics.com/amazon/candidate/exam_accommodations_default.aspx and to Schedule a appointment with accommodation you need to call Pearson Vue.

There is no linking to Accommodation and Certification Payment. Once you pay for the exam, you get the accommodation. Just don't forget to call Peason Vue and tell them to schedule with ESL to get benefited.