Hi Fazel,
Before we go further here, can I check that you do not intend to run this online? PsychoJS/Pavlovia cannot currently accommodate “dual player” type set ups.
If it is the case that you wish to run this locally, you will need to monitor 2 keyboard devices for keyboard events and then move on once space has been pressed on each of them. The first step here will be to distinguish between different keyboard devices, may I recommend taking a look at the documentation here Keyboard — PsychoPy v2021.1 on getKeyboards() which might help you in the right direction.
As a further point, I notice that youa re running 2020.2.4, could I recommend an upgrade since lot’s of bugs will have been ironed out since then, and that will make task creation much smoother!
Thanks,
Becca