Promotion is related to Sale. Sale is related to Product. Product is related to Soap. Soap is related to Self. 
Interview is related to Subject. Subject is a synonym of Purpose. Purpose is related to Explain. Explain is related to Understand. 
Promotion <--RelatedTo--> Sale <--RelatedTo--> Product <--RelatedTo--> Soap <--RelatedTo--> Self 
Interview <--RelatedTo--> Subject <--Synonym--> Purpose <--RelatedTo--> Explain <--RelatedTo--> Understand 