Flat is related to Paper. you are likely to find Paper in/at/on Drawer. you are likely to find Pencil in/at/on Drawer. you are likely to find Pencil in/at/on Classroom. 
Presentation is a synonym of Introduction. Introduction is related to Dear. 
Flat <--RelatedTo--> Paper --AtLocation--> Drawer <--AtLocation-- Pencil --AtLocation--> Classroom 
Presentation <--Synonym--> Introduction <--RelatedTo--> Dear 