There is no form for a chronology, below is a suggested template:
You need to head both papers for example:
In the XXXX court Case No. XXXXXXXX
Between [Full Name] Petitioner
[Full Name] Respondent
Prepared by the Petitioner (or Respondent)
The date of birth of the parties and children
The date of cohabitation if you argue seamless cohabitation to marriage
The date of marriage
The date of separation
The date of the petition
The date of the nisi if decreed
The date of the Forms E
The date of the FDA
Add other dates for hearings/other relevant dates if they happen. In financial proceedings a chronology is a simple document to give the judge a brief outline of some of the detail he needs.
The best thing is to keep it simple with bullet points identifying all the key events in chronological order. The aim is to provide a summary which focuses on the history and significant events to your case.