Problem glass shading

Hello everyone.
I followed tutorials to learn using blender.
But when it comes to make a glass shading I encounter some issues.
Instead of becoming transparent it becomes black and reflect everything or the blender’s landscape appears (see the screen shot I have others if needed).
I think I changed a parameter somewhere but I don’t know where, can someone as an idea of the problem ?
I will be grateful to read your answers :slight_smile:

Are you in Cycles or Eevee

Hey thanks for your answer !
On the image it was in Evee (and it works for cycles for this example)
But I don’t know why because if I create a new blender file with same shading in cycles I have this black cube :thinking: