ipad air 3 - ipad storage - "other" category

my brand new ipad air 3 64gb has a huge "other category" which i estimate is probably 15 GB or so. any way to see what this has so i can delete it? i have no music downloaded and i have icloud photo library turned on with optimize photos setting on. i set imessages settings to not keep anything more than 30 days. i have no apps larger than 1gb other than photos which is 22gb. but photos in the storage graph is already visible and accounted for and large. any ideas? thanks