Set writepermissions for folder in properties dont work ?

I wonder what the right way is to set write permission on a Folder.
I am in the properties for the folder I want to set write permissions to. The folder is named "Folder1"
Now when I click the "SecurityTab", I can see a listbox there wich grayed out checkboxes for "Allow" and all of these are Checked, then to the right I have unchecked checkboxes for "Deny".
I wonder if this is correct now, that "Folder1" has write permissions because this line execute that access is denied to "Folder1" ?
 
Directory.Move(Server.MapPath(sourcePath), Server.MapPath(destPath));
 
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