Indexing pages to be included in search results In order for your site's contents to be included in the results of your custom search engine, they need to be included in the Google index. The Google index is similar to an index in a library, which lists information about all the books the library has available.
Index Match within Arrayformula I have read some similar posts about this question about Arrayformula + IndexMatch, I know that Index is not available to use within Arrayformula and vlookup/hlookup should be used instead, however, I don't totally understand the mechanism inside.