Trials and block of trials randomization

**OS: Win10
**PsychoPy version: 2020.1.3

Hi everyone!
This is my first time doing an experiment in Psychopy. I have a question about trials and block of trials. I try to do an experiment with 4 blocks of trials with 15 trials each one. I would like to randomize as trials as blocks of trials. But I don’t find the way to do it. I’m very lost :frowning:

What options should I put in the experiment?
image

Trials and blocks:
image

I hope someone can help me with this.
Best regards,
Miriam

There’s a chapter on this in our book and there’s a demo in the demos menu of the application