Legally you can delay making contributions to your auto-enrolment pension for up to 3 months after your Staging Date without incurring any penalties, however you must still have your obligations completed and a scheme set up at your Staging Date.
During the postponement period, your employee will have to option to cancel the postponement and start the contributions into the pension scheme. Contributions will only be payable if your employee is classed as an eligible worker (i.e. one who is automatically enrolled) or as a non-eligible worker who is choosing to opt in. If your employee is an entitled worker and chooses to cancel the postponement period, then it will still only be them who has to make payments into the scheme.