[Koha] getting Dewey numbers into Koha

Hello all, We have been using Koha for a few months now, and are quite happy with it, but the work of a library system administrator is quite endless... We did not have any information from a previous system but author and title, which we all successfully imported. Now we have a list of Dewey numbers as well (in excel) that we want to import into Koha. We want to enter it in the 'classfication' field (And the 082 field - or is it possible to link them?). Is there any clever way to get it there? (or less clever, I will only have to do it once, as all new books will get entered with Dewey numbers) Please keep it simple, I am not a programmer! Just smart enough to do basic things... Thanks, Marty