To enter the Pattern editor Select it from the Top Menu or Press CTRL+P from any Editor.
The cursor is shown as an inversed (yellow) filled square in the left most field.
Move it using the cursor keys.
Moving left or right will move it along all fields in the row. To jump by Channel rather than field press and hold down control before moving.
The same is true for moving up and down the Pattern which will move in 12 row steps. The view is always held in the centre of the pattern Editor therefore providing maximum view above and below the current position.
For further Key commands refer to the Pattern Overview and the Keys.