The hands should not be rested on the table.

The hands should not be rested on the table and should be parallel to the keyboard when typing at all times.

wrong

correct
The wrist should be straightened and in line with the arm when typing.

wrong
correct

1. The top of the monitor should be at eye level
2. The keyboard is should be placed at waist level.
3. The backbone is should be straightened and rested on the chair.
4. The legs should be perpendicular to the floor.