You would just create a new boot menu entry.
Global->Boot Menu Templates->New Entry
Your example is for a syslinux menu so select syslinux/pxelinux for the type
In the contents just put

root (hd0,0)
kernel memtest

CloneDeploy will take care of the label and menu label.
Mark it active and save it.
Create a new default boot menu
Admin->Boot Menu->Default Boot Menu->Create Boot Files