There are two main requirements:
You had a pension in each year you wish to carry forward from, whether or not you made a contribution (the State Pension doesn’t count).
You have earnings of at least the total amount you are contributing this tax year. Alternatively, your employer could contribute to your pension.
There are other factors to consider if you or your employer have contributed to other pensions in addition to your SIPP or you have been a member of a final salary scheme.