All functions you want to overwrite, you can put it inside functions.php on your child theme, regarding pre-established functions:
get_header grabs header.php
get_footer grabs footer.php
get_sidebar grabs sidebar.php
get_searchform grabs searchform.php—if this is missing, WordPress simply renders a default search form
comments_template grabs comments.php
- get_header('custom'), for example, will grab a file called header-custom.php
- get_template_part('partname'), which grabs a template called partname.php
- include(STYLESHEETPATH . ‘/extrastuff/somefile.php’); use the path to your stylesheets to get to a file, you can also use TEMPLATEPATH