Override for new module positions is possible?

Hi, is possible to use the override folder to have new modules positions?
I've jet created in gk_override/myfolder
in myfolder I've placed my custom files templateDetails.xml and in subfolder /layouts I've placed my custom default.php where I've created (in both files) my new positions but it seems not work.

So, is it possible to do it with override and I forgot something, that's why not working yet or is it impossible?

Thanks in advance.

Hi

gk_override is only for as I can call it override of an override. Only files from /html folder can be put there. Some of the modules already has an override in template, so in order to change this files another override is needed. Module positions and changes to layout needs to be done directly in template files.