Learn Portuguese (Portugal): Quando trabalhas aqui?

In English, we use helper words like 'do' to ask questions, but Portuguese does not use these. You just use the main verb! The 'you' is also built right into the verb. Because trabalhas is the informal 'you' form of trabalhar (to work), the pronoun tu is clearly understood and usually dropped.

Is the word order always this simple for questions with quando?

Yes! You generally just put quando at the beginning, followed immediately by the verb. It literally translates to 'When work here?'.

Could I use a que horas instead of quando here?

Yes, but it changes the meaning slightly. Quando asks for general times, like which days or months you work. If you want to know the exact time of their shift, you would ask A que horas trabalhas aqui? (At what time do you work here?).

How would I ask this politely if I were speaking to someone I don't know well?

You would use the formal 'you' form of the verb, which drops the 's' at the end. The polite version of the question is Quando trabalha aqui?.