In any case the structure.
Tying a porch roof into existing roof.
Make a cutting on one of the sides of the horizontal roof beam on an angle.
After that to make it flush with the roof of the existing house cut the two outer rafters.
I would frame a wall up flush with the brick and then use siding to cover it from there on up.
Butt the first new truss against the old one.
Now take the 4x4 beams and erect them to the perimeter outside the porch about four feet apart.
When a shed roof ties into an existing roof the new roof could be a simple lean to that covers a deck or porch or it could be the shed roof of a substantial addition.
Tying in to an existing gable roof.
Tying a patio roof into existing house.
You have to do it thoroughly so that the rafters sit flush on it.
Attach the horizontal beam by using a nail gun.
Then mount new trusses on the new addition walls.
That fascia should be cut off where it is inside of the porch addition.