Hi,
for changing appearance - if it is only css you can override default css styles with css stylesheet that comes after default seblod one. If you also need to change html you need to do an override (or create completely new template, but that requires a lot of experience):
http://www.seblod.com/v2/documentation/seblod-2x/templates/1758-templating-101-overrides.html
You need to take care to override the right template and use right position in the folder, generally the right path is positions/search_type_name/view_name/position_name.php - other variations are described in the above article
view_name is the name of the view tab you are overriding (search/list/item)