Walls – How do i install a wooden door frame to a brick frame wall

If you're installing the frame in a new wall, then you should have 'tie-wires' embedded into a groove running up each side of the frame.
These are usually L-shaped lengths of galvanised wire about 4mm thick with the short leg of the L embedded in the groove in frame and the long leg sticking out.
The long leg is then embedded into the mortar between courses of bricks in the wall in at least 3 or 4 locations on each side of the frame.
If this is an exterior door then you should also have a strip of "DPC" (plastic sheeting) in the same groove running all around the frame and this keeps water from getting past the frame into the wall.

If you're replacing an existing frame, then it depends on how you've removed that one.
If you've knocked bricks out (or half-bricks) and will be laying new ones then you can continue as if this was a new wall and embed the tie-wires from the door frame into the new mortar between the bricks.
If you've just knocked an existing frame out, but left the brickwork as-is (still a neat rectangle without bits missing), then you'll probably have to drill through the door frame and mount the frame to the bricks with masonry anchors of some sort (something like the things often called 'rawl bolts' in SA). Choose positions where you would drill through into solid brick and not into the mortar between the bricks - those masonry anchors expand when you tighten them and, depending on the strength of the mortar, can sometimes just crack the mortar out of the joint.