Pass entered data between pages and save to database

Hello, 

I've 3 own pages, which are binding with my the same model. When I add some value in first page and clicked button where I set action Save data and open next page it works good also I have Business process where I can get record ID but this BP will stop. 

But now I'm entering next information on the next page and I don't know how to pass data from 2 pages to my the same BP or new BP and save it in the same record.

Creatio version: 8.1.2.39.42

Could you give me some advise how to resolve this issue ?

I'll appreciate any help.