Method of mounting a window frame in a roof window in a roof structure, said window frame comprising a mounting bracket comprising an angular bracket member having a first and a second leg connected integrally with each other, and a substantially plate-shaped base member having at least one opening for receiving locking means and being connected with an outer side wall of the window frame, the angular bracket member being connected to the base member in such a way that, the second leg protrudes outwards in relation to a plane perpendicular to the base member, in which locking means are provided for locking the first leg of the angular bracket member in relation to the base member in a locked condition, wherein the locking means comprise a stud having a head member and a screw thread member to cooperate with an opening in the base member with screw threads for receiving the screw thread member, wherein adjusting means comprising a closed slot are provided, said slot having pre-defined limited dimensions allowing adjustment of the angular bracket member relative to the base member in a plane parallel to the first leg along both a length axis and a height axis of the adjusting means and along any superposition of said two axes, if accommodated by the dimensions of the slot, and comprising the steps of: supplying a roof window comprising a window frame and a window sash, drilling a hole through a window frame side member, supplying the mounting bracket, abutting the head member of the stud against the second side of the first leg, such that the screw thread member is accommodated by the slot, mounting the base member of the mounting bracket on the window frame and mounting the angular bracket member on the window frame, applying a cooperating tool with a tip matching a pattern of a head member of the stud, screwing a screw thread member through the opening of the base member, thereby either untightening the stud to perform position adjustments of the mounting bracket, and tightening the stud to lock the mounting bracket in position, wherein a cover plate is provided to cover the hole after tightening the stud. a substantially plate-shaped base member having at least one opening for receiving locking means and being connected with an outer side wall of the window frame, the angular bracket member being connected to the base member in such a way that, the second leg protrudes outwards in relation to a plane perpendicular to the base member, in which locking means are provided for locking the first leg of the angular bracket member in relation to the base member in a locked condition, wherein the locking means comprise a stud having a head member and a screw thread member to cooperate with an opening in the base member with screw threads for receiving the screw thread member, wherein adjusting means comprising a closed slot are provided, said slot having pre-defined limited dimensions allowing adjustment of the angular bracket member relative to the base member in a plane parallel to the first leg along both a length axis and a height axis of the adjusting means and along any superposition of said two axes, if accommodated by the dimensions of the slot, and comprising the steps of: supplying a roof window comprising a window frame and a window sash, drilling a hole through a window frame side member, supplying the mounting bracket, abutting the head member of the stud against the second side of the first leg, such that the screw thread member is accommodated by the slot, mounting the base member of the mounting bracket on the window frame and mounting the angular bracket member on the window frame, applying a cooperating tool with a tip matching a pattern of a head member of the stud, screwing a screw thread member through the opening of the base member, thereby either untightening the stud to perform position adjustments of the mounting bracket, and tightening the stud to lock the mounting bracket in position, wherein a cover plate is provided to cover the hole after tightening the stud. supplying a roof window comprising a window frame and a window sash, drilling a hole through a window frame side member, supplying the mounting bracket, abutting the head member of the stud against the second side of the first leg, such that the screw thread member is accommodated by the slot, mounting the base member of the mounting bracket on the window frame and mounting the angular bracket member on the window frame, applying a cooperating tool with a tip matching a pattern of a head member of the stud, screwing a screw thread member through the opening of the base member, thereby either untightening the stud to perform position adjustments of the mounting bracket, and tightening the stud to lock the mounting bracket in position, wherein a cover plate is provided to cover the hole after tightening the stud.