First of all there is no sign of any exam for GSTP till date.
Section 148 of CGST Act 2017 says you need to get enrolled for GSTP by filing your form GST PCT-01 on GST portal. The proper officer will grant you registration certificate after say minimum 1 month. Such registration is valid for 1 year from the date of grant of certificate unless the GSTP passes the exam as conducted by the council.
With regards to exam and syllabus it will be intimated in due course on your registered mobile number and e-mail id or else you can keep on checking the common portal for updates.
GST Practitioners Required To Pass Enrollment Of GST Practitioners Examination Before 31st December, 2018
To make compliance easy for businesses the Government has introduced various initiatives like GST Practitioners and GST Facilitation Centres. Section 48 of the CGST Act provides for the authorisation of an eligible person to act as approved GST practitioner.