What is your input for the writer? If you don't have any features to feed into it currently, you can use the Creator transformer to create a feature. Also, you may want to read into the format attributes of the writer...filecopy_source_dataset and filecopy_dest_filename.
https://docs.safe.com/fme/html/FME-Form-Documentation/FME-ReadersWriters/filecopy/filecopy.htm
Alternatively, I usually use either a PythonCreator or PythonCaller when I need to create directories. The below code in a PythonCreator will create the Run_ folder, you will just need to update the dir variable to where you want the folder to be created. You can also link the dir to a published parameter in the code.
import fmeobjects
import os
from datetime import datetime
class FeatureCreator(object):
"""Template Class Interface:
When using this class, make sure its name is set as the value of the 'Class
to Process Features' transformer parameter.
"""
def __init__(self):
"""Base constructor for class members."""
dir = "E:\\your_path"
new_dir = os.path.join(dir,"Run_"+datetime.now().strftime("%Y%m%d"))
if not os.path.exists(new_dir):
os.makedirs(new_dir)
pass
def input(self, feature):
"""This method is called once by FME to create FME Feature(s).
A created Feature is emitted through the self.pyoutput() method.
Any number of Features can be created and emitted by this method.
:param fmeobjects.FMEFeature feature: Dummy FME Feature passed in by
FME. It can be ignored.
"""
newFeature = fmeobjects.FMEFeature()
self.pyoutput(newFeature)
def close(self):
"""This method is called at the end of the class."""
pass