Can you be more explicit?
Where is the value you want to set in the Date attribute?
I you want to set actual date time:
you can also set the begin of current day, the end of current day or set the date value of oher object
I hope this can help you
In a change object action you need to select your date attribute.
Now you have different options. You can choose a date from a token as CurrentDateTime, you can use a timestamp from a DateTime variable or attribute on an other object, you can use parseDateTime() to parse a string to a date time (remember to add the time format),...