Here is a short overview of the default keybindings:
j/k/l/;::
-Direction keys (left, down, up, right). They are on your homerow (see the mark on your "j" key).
+Direction keys (left, down, up, right). They are on your homerow (see the mark
+on your "j" key). Alternatively, you can use the cursor keys.
Mod1+<direction>::
Focus window in <direction>.