This route is not difficult at all, and it is ideal to do with kids.
Take the path that goes from Biescas towards the cemetery, which is a tarmac path until there. You will come to cross straight after; take the direction Gavín-Yésero. At that point the trail changes from a path to a track, with old walls covered in moss along the way.
Soon after, the track narrows and continues on with abundant hedgerows until you arrive at the outskirts of Gavín village.