How can I save a statement from Postgresql in order to open and see the results in Sqlite?

Hei, I'm the beginner of beginners in working whit PostgresSQL, and a teacher give me a task to do that i have no idea how it works....so, i will explain what he give me, and i would love to hear a person or more grin emoticon that can help me... 1.What i have: files with coutries,rivers,population of the world 2.What i have to do: a) use a statement that will cut a polygon(in my case..cut a polygon that represents a country that i chose) b) use a statement that will take out the rivers that intersect with my polygon c) save the statements as csv, txt file(in order to se what statement i used) d) export in sqlite and se the result there( and he says that i have to give him just the sqlite and the text,csv file with the statement that i used) 3. What i've done yet: i've connect to a server...i've create a database...and that's it... Any response that help me progress is good.Thanks !!!