"Casilleros"

In an office, you can say 'pigeon hole' or 'cubby hole', but in class you can also tell pupils 'Put your things in your tray' (they usually have a tray in the pigeon holes) or just tell them 'Put your  worksheets away tidily, please'. If they have plastic folders then you can also say 'Put the worksheet in the folder.'
Click on the link below to hear how to pronounce these words.

"Conserjeria"

You may simply say: "Caretaker's office"

Departamento de orientación

You may say: Guidance department

The person giving counselling is the counsellor. They provide, among other services, careers guidance.