Attach a sill plate to the house between the two side supports of the porch.
Attach porch roof to side of house.
Cut each of the house ends while continuing installing the rafters so that they fit the top of the rafter beam perfectly.
That is why everything must be stable and strong.
About this you must make sure that the porch as well as the house can cope with the structure.
In this post in roofing with pics.
With either nails or using the mounting brackets attach the beams to the floor boards of the porch.
Attach the rafters to the ledger boards and settle joists.
Place the rafters on 24 centers attach them to the settle joists and beams toward the center.
Attach the rafters to the house with joist hangers which supported by ledger boards.
With the beams in place you will now have the outline structure for the roof frame.
Put 4x4 beams against the house also having these four feet apart from each other.
Patio roof connects to a ledger that firmly attaches to house framing.
Nov 29 2014 expert advice on how to build an outdoor patio roof or gazebo with illustrated step by step instructions and construction diagrams.
A new roof is a heavy one.
After that to make it flush with the roof of the existing house cut the two outer rafters.
It also means that you have to make sure that no parts of the house and the roof are rotting and weak.
If the house is sided with shingles or lap siding simply slip the metal s top edge up under the bottom edge of the shingles or siding as far as possible.
The sill plate or piece of wood that secures the supports to the roof should sit flush to the top edges of the roof support columns.
Now you can begin assembling the outer rafters and attaching the rafter beam to the edge of the roof of the house.