You might want to do some basic learning paths. You can use a (non) persistent object as helper entity. You can pass that entity from one page to the other by passing this object as parameter in the microflow to open the next page. Do note that non persistent objects can also be attached to the user session and thus retrieved in a microflow by retrieving the current user and then retrieve the attached objects again.
Garbage collection will take place when the object is no longer in use. That's why attaching it to the user session it will not be garbage collected untill the user logs out.
Regards,
Ronald