If you have more results than your specified limit, the results to your API query will also contain a nextPageToken:
This can be used to repeat the query, including the token, to get the next results up to the limit again.
For example, if you wanted all submissions from the services kapp for a form with the slug of contact-us, the query would look something like this:
Note that the maximum available limit is 1000.
If you were to receive the nextPageToken provided above, you could get the next 25 by going: