If you go walking in Spain you will see many types of marking. This will help you undersand what they are.
Senderos Locales - Local Trails
White and green and with the acronym SL.
An SL route is less than 10km.
Senderos de Pequeño Recorrido - Short-distance trails
White and yellow and with the acronym PR.
A PR route requires no more than one day, between 10km and 50km.
Senderos de Gran Recorrido - Long Distance Trails
White and red and with the acronym GR.
A GR route requires more than one day, with a minimum length of 50 km.

Translations:
Continuidad de sendero = Continuation of path
Cambio de dirección = Change of Direction
Dirección Equivocada = Wrong way or Not this way
Some more info about GR routes
The Grande Randonnée (French), Groteroutepaden (Flemish - Flanders) or Langeafstandwandelpaden (Dutch - The Netherlands), Grande Rota (Portuguese) or Gran Recorrido (Spanish) is a network of long-distance footpaths in Europe, mostly in France, Belgium, the Netherlands and Spain. The trails in France alone cover approximately 60,000 kilometres (37,000 mi). Trails are blazed with characteristic marks consisting of a white stripe above a red stripe. These appear regularly along the route, especially at places like forks or crossroads.
The network is maintained in France by the Fédération Française de la Randonnée Pédestre (French Hiking Federation), and in Spain by the Federación Española de Deportes de Montaña y Escalada (Spanish Mountain Sports Federation).
Vocabulary for hiking in Spanish Click Here
Click on the links to see the most popular activities that you can do in these places:
Note that the booking system uses a Spanish system and there is no involvement of any American company and no US tariffs.