Subsection (1) specifies the provisions to which the modifications in subsection (2) apply.  These are provisional orders (which require to be confirmed by Act of Parliament) and special procedure orders (within the meaning of the Statutory Orders (Special Procedure) Act 1945 and which require to be subject to special parliamentary procedure) under any pre‑commencement enactment where the power to make, confirm or approve such an order is exercisable by the Scottish Ministers by virtue of section 53.
Subsection (2) makes modifications to ensure that such provisional orders become subject to confirmation by an Act of the Scottish Parliament rather than an Act of the UK Parliament and for such special procedure orders to be subject to such special procedure as may be provided for by the Scottish Parliament rather than the special parliamentary procedure provided by the UK Parliament in the 1945 Act.
Transitional arrangements for special procedure orders were provided by the Scotland Act 1998 (Orders subject to Special Parliamentary Procedure) Order 1999 (S.I. 1999/1593) prior to the Scottish Parliament prior to the Scottish Parliament making its own provisions.
Commentary Part V: Miscellaneous and General Details of Provisions