If you just want to exclude ANY folder which starts with a '.'
then you're looking to exclude the pattern '\.'
, ie any folder path which includes a '.'
preceeded by the path separator '\'
, which you do with the filter:
-\.
This can be tested in the Look In field by setting the expression type to Plain Text and applying a location filter, e.g.

If you want that location filter to permanently apply to all searches then add -\.
as a persistent filter:

Drive specific filter
If you want it to only apply to searches on the 'N' drive then it's a little more complicated. You'd need to specify the filter as a regex, e.g. test with
N:\Search;-:regex:^N:.*\\\.
Then if that's what you want add a Regular Expression persistent filter of:
-^N:.*\\\.
