If you use Simple Assessment
Go to Admin > Year End
Under 'Simple Assessment' in the Recommended section you will find a link which says 'Click here to copy final assessment data to Baseline and add student assessment targets'.
Once you click this you will be presented with the Simple Assessment Markbook.
Select the Assessment you wish to copy data in, all subjects - either all years or a specific year group.
Select the current academic year and Baseline checkpoint and then click Load Markbook.
It may take a moment to load this, especially if you have a large number of students. Once you see the markbook, against each subject, click the fill gaps drop down menu then click Copy previous checkpoint.
If you use Steps Assessment
Go to Admin > Year End
Under 'Steps Assessment' in the Recommended section you will find a link which says Click here to copy CP6 to Baseline
Select All Subjects and All Years and click choose.