I used this book as did my wife to help us to learn Spanish Grammar:
USO De LA Gramatica Espanola: Nivel Elemental – New Edition 2010 (Revised and in Colour) (Spanish) Paperback
by Francisca Castro Viudez
It made a great difference to us and brought our Spanish up from barely passable to a couple of levels above passable in less than 12 months.
Like all Spanish courses, it requires effort on behalf of the person learning, and there is no “magic” way to learn any language.
Available from Amazon.