How do i get path information for? GOOGLE_APPLICATION_CREDENTIALS

I am using Flutterflow (FF) to create an app. I build the Firebase db before adding Algolia, so now I need to get the documents indexed and I am not sure how. FF told me I need this to move the information:
My question is about the last line of instruction to upload search information to Algolia. The full set of instruction requests this:
LOCATION=us-central1
PROJECT_ID=<firebase_project_id>
ALGOLIA_APP_ID=<algolia_application_id>
ALGOLIA_API_KEY=<algolia_api_key>
ALGOLIA_INDEX_NAME=<algolia_index_name>
COLLECTION_PATH=<firebase_collection_name>
GOOGLE_APPLICATION_CREDENTIALS=</path/to/service/account/key>*
** npx firestore-algolia-search
*

how do I get the directory structure. If I cannot get the path I can upload manually or by file. I only want Algolia to make searchable one field in my document.
The examples look like this:
[
{
“firstname”: “Jimmie”,
“lastname”: “Barninger”,
“zip_code”: 12345
},
{
“firstname”: “John”,
“lastname”: “Doe”,
“zip_code”: null
}
]

How would I get Algolia to know that the one field I want searched is associated with a particular document.
The field I want searched is called “Modern” and then there is 5 or so sentences in that field. I don’t want to upload manually but I don’t think I am going to figure the other way out. So how do I get my “Modern” attached to a document number so it gives the correct results.
And thank you
There is only 150 docs/fields to upload, so whichever way is faster is good with me.

Edit:
Another thing I might do is set up my Algolia with a new field, then cut and paste all my previous Moderns into the new field that Algolia would automatically pick up. So I could set up Algolia to search “modern1” which is an entirely new field. Would that be easiest. I have to figure this out because there are 3 more apps planned, this is our test app.