"El" is masculine singular article "the". El auto = the car. El cuaderno = the notebook. El reloj = the watch. "Al" is the constraction of "a el" (to the). Al auto = to the car. Al cuaderno = to the notebook. Al reloj = to the watch. This will happen only if the verb that preceeds the noun requires the preposition "a". Voy al centro = I go to downtown. Le dije al conductor = I said to the driver. But if the verb does not require the preposition "a" but a different one or none at all... No veo el problema = I do not see the problem. Mi hermano está con el coductor = my brother is with the driver. I hope this helps.