Is there a guide how the touchpad (part No BA97-03985A) can be replaced?

The replacement is really simple: just remove the battery (see Samsung ATIV Book 9 Plus Battery Replacement). The touchpad is mounted below the battery with 4 screws (you need a really small phillips screw driver). The spacers (and also the mounting plate) are fixed with adhesive tape and can be removed (by gently pulling) from the old touch unit.