Hello,
I believe there is a confusion here. In free version you can not set users permissions … and since version 2.1.6 only administrators can view the booking system.
To change this go to file dopbs.php @line 1027 and remove this line:
$this->vars->role_action = 'manage_options';
I will see if in the next update, I can add user view permission, like in PRO.
Thank you