shed roof over porch of 1 1/2 story house

[Park e]

Using HD 7 Platinum.
I'm having difficulty putting a shed roof (3/12) over the porch. House roof is 10/12. ! 1/2 story house 32' long (first floor) with a 19' long 1/2 story second floor. (All front of structure perspectives.)
Porch is 18' long and covers 13' of the single floor and then adjoins 5' of the exterior wall (under 2nd floor). Any ideas?