If you go leftwards, you go to the left, or you keep moving that way. You can look leftwards, turn leftwards, or say that a line on a page runs leftwards. It is a little more bookish than to the left, which is what most people say in daily talk. British English likes leftwards with an s; American English often writes leftward with no s. Both mean the same thing. It is only about direction — the left side of a body, a road, or a page. It is not about what is left over, and it is not about politics (the left).