I also have the same problem, bought the Essential Morph and Skin pack, and can't find anywhere any way to apply aging to character texture, which was advertised on the website.
I tried loading the CC1 Base_Substance, it takes 10 minutes or more to load but still does not give me anything, the Load Appearance Editor button is still disabled...
If the Appearance Editor is still not active, then it is likely you are not loading the correct CC1 character. It must be one of the two shown below. Do check that the thumbnail has the circled CC1 indicator on it and not CC3. If you load one of these two avatars you should find the Appearance Editor will become active. Note: Do ensure you have selected the CC1 character in the viewport (it will then have a yellow bounding box around it).
If you are looking for the avatars that come with the CC Essentials Morph & Skin pack, just go to Project > Character (Avatar) > Base > Essential Morphs in Content Manager (see below).