Work up from the initial row starting at the lower corner in a diagonal pattern staggering the shingles to prevent gaps.
How to attach a metal roof to a wall.
The flat roofing material must go up the wall a minimum of 12 or up the wall and over the top of the wall if the wall is less than 12 high.
Now we can install our roof panels.
Apply the sealant tape along the center of the entire eave and remove the tape backing.
Install base flashing under shingles or over metal roofing material.
Remember sealant tape goes between all layers of metal.
Lay the starter row of metal shingles at the drip edge and affix to the roof with metal roofing nails.
Make sure the panel is square to the eave of the roof so that all of panels installed afterwards are straight.
Before you install metal roofing repair any damage to the wood under the shingles.
Next use 1 inch nails to secure some metal edging to the perimeter of the roof.
Then cover the entire roof with a layer of insulation and secure it with a staple gun.
Here is an attempt though maybe not a very good one to make the roof flashing serve also as a through the wall flashing with a tile roof.
How to attach roof shingles to a tool shed how to build a tin roof cover tin roofs feature corrugated sheet metal installed with the grooves running downward to encourage water to drain off the roof.
Installation using exposed fasteners.