Portuguese has two past tenses equivalent to the English simple past. One is the pretérito perfeito (quis) and indicates a completed action. It's closer to the English "I've wanted". The other one is the pretérito imperfeito (queria), which implies a continuous and unfinished action, closer to the English "I was wanting, I was meaning"
Ele queria trabalhar lá. (He wanted to work there. He'd been meaning to be work there for a time - not only once, but for an INdefinite amount of time that's why you use the IMperfect.)
Ele quis trabalhar lá. (He wanted to work there. He had this wish once, it's in a definite period of time, it doesn't matter how long he'd been meaning to work there, it just means he once wanted to do it, as plain as it gets.)
"Queria" is also used as "I would like" or "I wish".
Queria poder comprar um carro. I wish I could buy a car.
"Quis" is also used as "have wanted".
Sempre quis comprar aquele carro. I've always wanted to buy that car.
So, to wrap it up:
- Indefinite time = imperfect (queria)
- Definite time = perfect (quis)