Jira Migration to Gitlab cloud

I am trying to integrate Jira into Gitlab.

For Integration, I am unable to understand how Transition ID’s work and if that approach works, does it help to get all the Jira issues migrated with all the columns like comments, status assigned to etc.,

While importing using csv format does Git limit to only 2 columns? if not how does it work for other columns like comments, date opened, status, Epic etc.,