Using Classification to Create Multiple Sets of Marketing Channels

Hi,

I'm exploring the possibility of using classifications in order to create multiple sets of Marketing Channels. For example, one of our main traffic-generating channels under the "Marketing Channels" dimension is "Social Networks"; I'd like to create a dimension called something like "Marketing Channels2" that breaks "Social Networks" into "Paid Social" and "Organic Social" channels.

I'm assuming to get started on this, I should navigate to Admin Console>Report Suite Manager>Settings>Marketing Channels>Marketing Channel Classifications. However, (see attached) I only see options for classifying "First Touch" and "Last Touch Marketing Channels"...I see no option for simply "Marketing Channels." Help!