On the bottom of the page the link sends you to should have the format.
Templates
The CSV files must have the values in a particular order to be processed correctly. The Excel templates below can be used to help format your data correctly. The file formats are:
Local Users: userid,user_name,enabled{true|false},password,[role_name],phone,email,sponsor,title,department,designation
Endpoints: mac_addr,status{Known|Unknown},description,device_type,device_vendor,os_version,os_type,location
NADs: ip_addr,name,description,coa_port,coa_capable{true,false},vendor_name,tacacs_secret,radius_secret