If you made corrections to your tax return, you will get a new tax decision. In that case, the payment date of your tax refund or the due dates of your back taxes will probably be postponed. You can find the new payment or due dates on the new tax decision.
Everyone working at a construction site or on an installation project must have a tax number. You can get your tax number at a tax office. If you already have a tax number, ask for it to be included on the public register of tax numbers. You can start working at the construction site after your tax number is registered.