You only need an auto-enrolment pension scheme in place by your staging/duties start date if there’s someone to auto-enrol on this date. If there’s no one who needs to be auto-enrolled then there’s no need to have a pension scheme in place. However, it may be useful to decide which pension scheme would be used if the person or people you employ actually need to be enrolled (or ask to join).
Even if there are no employees to be auto-enrolled, you will still have a duty to write to your employees and complete your declaration of compliance.
The staging date is when the legal duties begin. This would have been determined by the size of your largest payroll as at the end of April 2012.
If you started trading after this date, The Pensions Regulator should have written to you to provide you with a staging date or you can find this information out by inputting your PAYE reference at www.thepensionsregulator.gov.uk/employers/staging-date.aspx