Thanks @mitchbaylis. Maybe I was too focused to create data in the backend and show to the guest in frontend without saving anything on database before final submit.
I use toolbox listofnumbers to create a list but a bit confused how to show lets say 4 empty form to the guest to fill it inside RG if I make data source reservations (like page data) and not listofnumbers list as data source (to navigate between forms) - or I am not catching something here? 
And maybe a bit about database - so reservations data type has a field guest list (as list), also separate data type for guests (all necessary details to collect). In order to create empty forms I need to create entry to reservations and put all guests info into list - here maybe question about mapping different type of fields from guests to one guest list? Or all the fields in guest data type should be as list (list of first names, list of last names, etc.)