My dictionary says that proveer is a regular verb, but it doesn't look right to write proveió. How do I conjugate it? Like leer?
Yes, it's like leer, so the past tense is proveyó.
I you want to conjugate any Spanish verb, the Website of the Real Academia Española provides it. Just enter
http://www.rae.es , press on the first link upleft (Diccionario de la lengua española), enter the word in the appropriate field, and you'll get its meaning. If the word is a verb, simply press the blue square in its definition and, voilà, you'll get the conjugation.