Thanks for the doc.
I want to ask that all that forms mentioned in SLM processing data model need to be migrated or few ?
that depends on the data you have and how you have setup your Service Targets.
The document will help you to determine what data is where, dependant on Service Targets, Milestone Actions, etc.
You need to do a little investigation to see what data is required to be migrated based on your requirements.
I am facing an issue on this, when the SLA's are migrated, all the milestones related to that ticket are not getting migrated.