You will need to set up an EYFS class for these students, in order for them to access the Early Years formative statements, which you can do by going to Admin > Classes. Under the Create Classes tab, select Reception as the Year, select the Group (form) you require (so that you don't get mixed up with the EYFS class already present) and the Subject Early Years Foundation Stage, then add new class.
This will create a class called '0 PUF' under Year Reception on the classes front page.
Now, in Admin > Classes, go to the Add Students to Class tab and select both year 0 and year 1 then tick the EYFS class you have just selected underneath the forms (0 PUF in this instance). It will display all students in Reception and Year 1 so tick the students required for this class in Year 1, and Save Classses at the bottom of the page.
The class will now be in black instead of read, meaning it contains students but no staff.
Next, go to Add Teachers to Class. Select the teacher you wish to assign to this class, so they can view the markbook under My Subjects. Select Year Reception (as the class is set up in Early Years Reception).
This will add the class to the teacher's existing classes, all visible under My Subjects with their login. This markbook will display the Early Years formative statements for assessment purposes.