It is also important that your arms and hands are arranged in a natural way.

You do not need necessarily come back to the base position, after a key has been pressed, although, your forefingers should keep their base position whenever possible. During touch typing, you reach other keys starting from the base position. The rest of the fingers (except for the thumbs) should be placed along the same row as the forefingers. For QWERTY keyboards the middle means keys: 'F' and 'J'. The most important thing is to place your forefingers in the middle of the third row of keys (counting from the bottom).