@annao63476039 The best option is to restrict the user access to the folders under which you would need them to search and remove access to other parts of the content if they do not use other paths, this would ensure when these user /group uses the search they will get results from the folder they have access.
If you cannot restrict access for these users and would like to still restrict search then overlay the below path and set the value to the folder you need the search to work
/libs/wcm/core/content/search/searchpanel/facets/path
Once you do this, the search tool in classic UI will always search under this folder.
Please note, I do not have 5.6.1 instance the path shared is from 6.x version of AEM, but I would expect it to be same .
Also as AEM 5.6.1 is not supported anymore, do consider upgrading to latest version of AEM from new features.