I am already finished with this part, but I wonder what the right way to do
it is...

I am nearly done building a 4x8 shed that backs up to my garage. I did the
roof today. How was I supposed to do the last row?

I cut a half width shingle to fit, nailed it on, and covered the nail heads
with a tarry patching compound. Since it is shielded by the garage roof
overhang it will never get very wet, so I figure my method will be adequate,
but what is the right way?
Thanks.