[Gocamino] Peregrino's passport

[Gary Hammond]

Hi All, My wife and I are going to be doing the last 100 km of the Camino
this month (Its all of the time we can fit in). What point do you recommend
that we start at to get credit for the last 100km?
We have Peregrino's passports that we received a couple of years ago as well
as letters from our Parish Priest. Where must we go to have the passport
initially validated/stamped/approved? 
Thanks
Gary and Jane