Is desc used for arranging data in descending order, but i thought that it is used to 'describe' the table.

Answer 1

Yeah it's used to order the data in descending order when you query them.

For example you want to get all names from the person-Table in descending order:

SELECT name
FROM person
ORDER BY name DESC;

Just replace DESC wit ASC to order it in ascending order.
But ASC is anyway the default-value. So it's used always when you don't specify it.