This is a link to a manual on the website of the Dutch Confraternity of Saint James (NGSJ). It will tell you what free navigations apps you can use on your smartphone, and how to load KML and GPX tracks into it for (nearly) all camino's in Spain and other countries in Western-Europe.
This site is run by Ivar at in Santiago de Compostela.
This site participates in the Amazon Affiliate program, designed to provide a means for Ivar to earn fees by linking to Amazon