There are many commands to move you around in a file. It's important to know that there are two types of movement: selecting and scrolling.
Selecting is moving the current selection (usually an insertion point) around in the file.
Scrolling is when the file window is scrolled to reveal new parts of the file. You can scroll a window up, down, left, and right. Scrolling does not always affect the location of the selection.
Selection commands can cause scrolling to occur if the place you are selecting is not visible in the window. For example, if the cursor is on the bottom line of a window and use the Cursor Down command, the window is scrolled to reveal the line below.