tuning troubles - my exports arent exported as packages

hi ! i am very new to the cc community, ive looked around to see if anyone else has had this problem and i think they haven't because i just am really doing something wrong! i am following this sims4studio.com/thread/1324/make-basic-change-items-tuning tutorial, trying to make some pre-existing toilets off-the-grid but when i edit the tuning and then export it my files aren't exported as files that i can then use again in s4s and edit the meshes of! im sorry if this is super obvious, i just can't for the life of me figure out what i'm doing wrong :( 

any help would be so appreciated !! thanks so much!