After you ve correctly installed the valley flashing you can install the drip edge which is corner shaped and will be attached with nails along the edge of the roof.
How to install flashing on a roof edge.
Tack the edge in place with a roofing nail every foot or so.
Bend the corner flashing tightly around the corner.
Drive the nail through the drip edge into the roof surface not through the fascia.
Roof shingle over step flashing.
Lift the shingles and slide the top flange of the drip edge underneath.
Step flashing on roof peak.
Measure the length of the eave you need to cover with drip edge using a tape measure.
Install the drip edge by fitting it on the roof eave pushing it tightly against the edge of the plywood and.
If you do not wish to form your own corner flashing you can buy pre bent pieces and cut them to size or use a piece of corrugated aluminum which is easier to bend.
Install the step flashing when the siding is installed it should be tucked behind this piece and then consecutive courses lapped over it.
The remaining siding on the sidewall will overlap the step flashing and nail.
Start the installation at the lower edge of the roof and work your way up toward the peak.
Cover the nail heads with roofing cement and stick the felt down.