What this suffix does
-ward (and its variant -wards) attaches to a direction word to form an adverb or adjective meaning "toward that direction":
in → inward
out → outward
up → upward
down → downward
back → backward
for → forward
home → homeward
on → onward
It also works with the compass directions: north → northward, south → southward, east → eastward, west → westward.
BrE vs AmE: -ward or -wards
British English tends to prefer the -s form: towards, backwards, afterwards, inwards, outwards.
American English tends to prefer the form without -s: toward, backward, afterward, inward, outward.
Both are correct and understood everywhere, it is just a regional spelling difference, not a meaning difference.
Two exceptions: wayward and awkward
"wayward" (rebellious, headstrong) and "awkward" (uncomfortable, clumsy) end in -ward, but have nothing to do with direction. Don't try to apply the pattern to these two, just learn them as their own words.