Attach Porch Roof Beam to Side of House
You seem to have posts at the face of the existing wall. If that's the case, you don't really need to attach the beams other than to hold them in place in a superficial manner.

Otherwise, joist hangers or full bearing on framing in the wall. In either case you need suitable backing structure on which to mount the hangers or bear the beams. If you don't have studs in the right locations, look into top-bearing hangers that you can fasten to the top of your wall plates. 

The fact that one beam appears to connect at an outside corner may complicate things a bit. You won't have room for a standard hanger. You might be able to attach around the corner by flattening out one leg of the hanger. That also may be a good location to cut into the corner stud cluster and bear directly.