Prerequisites
GCP account
Open Console
Open Menu > Cloud Storage > Bucket
Open the bucket and click on the file which you want to copy
Copy the URI of file

Open Cloud Shell
Paste the code below
$ sudo gsutil cp –r <URI_of_File> /mount_directory

It will copy the file from Cloud Storage Bucket into filestore file share directory
Copying data from a Filestore file share to a Cloud Storage bucket
$ sudo gsutil cp –r /mount_directory gs://<Bucket_name>/folder_name
It will copy the file from file share to cloud storage bucket

You can use the below command also to copy the file to or from filestore instances
$ gsutil rsync -r mount-directory gs://bucket
It will copy the whole files containing in mount directory into bucket
