Add note on datalad clone

notes.txt

@@ -5,3 +5,9 @@ The command "datalad save [-m] PATH" saves the file
 (modifications) to history. Note to self:
 Always use informative, concise commit messages.
 
+The command 'datalad clone URL/PATH [PATH]'
+clones a dataset from e.g., a URL or a path.
+If you clone a dataset into an existing
+dataset (as a subdataset), remember to specify the
+root of the superdataset with the '-d' option.
+