Verb conjugation of "valer" in Spanish

My parents were Italian, but the first language I learned was Spanish, since we lived in southern Spain. Very close to Gibraltar. When I was older, like twelve I moved with them back to Lucca in Italy.
Vocabulix includes a vocabulary builder for many languages, Spanish and German are just the ones that have the predefined sections. Generally speaking you can invent your own set of expressions and drill them on the speed train.
In school, we now are learning the grammar part, more specifically, the participles and so on. I understand it at all, but the conjugations, boy they are tough. A lot of patience is needed.