[Koha] Migrating from Athena -- Koha-MARC DB links

Has anyone switched from Athena to Koha or are in the process? I could use some help with the MARC DB links. The problem I'm having is mapping the items fields. It looks like I should be mapping 852 here. On the item fields test I'm getting ALL items MUST: -be mapped to the same tag -and they must be in the 10 (items) tab Do I need to map all of the items from the drop-down menu? -- Tim McMahon Technical Services West Liberty Public Library http://www.wlpl.org