The most efficient way to do new KWs to an existing campaign in editor is this:
Go to make multiple changes with campaign selected (only). add in only two columns: Ad groups and KWs. From there, upload the new additions. Then select campaign, go to ad groups, then select all the ad groups that have no ads. This can be done by sorting the list based on error status (error is no ad in ad group yet). Selected ad groups, then make ads for the ad groups.