Simple guide for making replication for a NativeScript app

I don’t know much about Couchbase Server and Couchbase Lite, and the docs are not friendly for beginners.
I have a NativeScript mobile application that use Couchbase Plugin
for creating two databases,
How do I make use of Sync Gateway for replicating?
Is Couchbase Server vital for using Sync Gateway? I just want to make simple persistence (on-disk) replication for the two databases.

In the Couchbase Plugin readme, it only provides this block of code about syncing with no description:

const push = database.createPushReplication(
‘ws://sync-gateway-host:4984/my-database’
);
push.setUserNameAndPassword(“user”,“password”);
const pull = database.createPullReplication(
‘ws://sync-gateway-host:4984/my-database’
);
pull.setSessionId(“SomeId”);
pull.setSessionIdAndCookieName(“SomeId”,“SomeCookieName”);
push.setContinuous(true);
pull.setContinuous(true);
push.start();
pull.start();

Where should I write what?
I don’t want my database to have any user or password requirement.

What is the sync gateway json configuration file? Where should I put it? What should I write in it? I’m confused and have many question which official docs don’t help.

I am on Windows platform and the official Couchbase Sync Gateway docs for starters is incomplete and scarce, in my opinion.

Thanks,
Regards.

For Sync Gateway configuration docs go here: https://docs.couchbase.com/sync-gateway/2.5/config-properties.html

Note that the project you linked (Nativescript) is neither supported nor maintained by Couchbase so don’t expect too much. Sync Gateway is another story and the above linked document should help.