No problem! As I understand it:

1) You can call the person listed in the job-posting to get further information about the job
2) Apply online with the 5-step formular, an application and a CV
3) If you then are called for an interview you get two e-mails. One with a simple test and one with a calender booking link to book the time for your interview.

The interview will take plase at their office, so I do not see any interview by phone.

Good luck with your application and possible interview!