Since I don't have the Ancestry app installed at the moment, I'll use the web interface for these examples.
Whether you have a subscription or not, you can learn more about the records from the main search page for the collection.
Glamorganshire, Wales, Anglican Baptisms, Marriages and Burials, 1570-1994.
On the top right, a banner shows us this collection is part of a partnership agreement.

Underneath the search form, Ancestry gives us Source Information (and under that,
About the Database information).

Ancestry.com. Glamorganshire, Wales, Anglican Baptisms, Marriages and Burials, 1570-1994 [database on-line]. Lehi, UT, USA: Ancestry.com Operations, Inc., 2020.
Original data: Glamorgan Baptisms, Marriages and Burials. Wales: Archives and Records Council Wales.
Use the information given, you can learn more about the records at the website of the repository which holds the records. You can also learn a little bit about how the records are arranged and which records are included in the database by looking at the Browse Box on the right-hand side of the page.

Ancestry subscribers can also get more specific data about which register is being referenced from the individual record page. Here we don't get an archive reference on the record page, but we can see from the app that the baptism date was 2 Sep 1914 and the baptism place was Cardiff, St John, Glamorganshire, Wales.
The most straightforward path is to get access via Ancestry Library Edition. Let's suppose for the moment that the Archives has decided not to continue the partnership and the image is no longer on Ancestry. What then?
- The Archifrau Cymru / Archives Wales catalog may say which partners now have digital images.
- Use GENUKI's pages for Cardiff to find more information about Church records for the area.
- Do a place search and a keyword search on FamilySearch.org. See the FamilySearch Wiki articles FamilySearch Catalog Places Search and FamilySearch Catalog Keywords Search for details.
- Contact the local Family History Society to see if they have transcriptions or online images. Find local societies via the Family History Federation (formerly the FFHS, The Federation of Family History Societies).
- Check other big sites like Findmypast. Article on Parish baptisms 1538-2005.
- Use finding aid sites like DustyDocs or UKBMD's listings for Parish Registers.
- Use finding aid sites like Linkpendium and Cyndi's List.
- Do a Google search for the parish name (when known) and "baptisms" to see if you can find transcriptions or published works, or news articles about which site may be offering access to images.
Adding information to indexes on Ancestry
Subscribers on Ancestry have two ways to submit alternate readings of names.
Use the link to Add or Update Information underneath the green View button. (Report a Problem is for cases where the linked image is not the correct register or correct register page.)

Use the "people" icon to the right of the image number at the bottom of the Image Viewer to open the index underneath the image. The information that can be corrected will show as a link.
