1. What do you mean by "no feedback"? Did you email certifications@splunk.com? Give them some time to respond. Especially that as far as I've heard, the EDU team has time off until tomorrow, I think.
2. In order to schedule your exam you have to register with pearsonvue. That's it as far as I remember since for Power User you don't have any strict prerequisites required to complete beforehand. You can do a User exam first but it's not mandatory.
