The pygeoapi config is the place to start when configuring a new service. The file starts with some general server configuration and then presents a list of collections. Each collection has a data store configuration referencing one of the available data backends. A common data provider is the OGR/GDAL provider which gives access to a multitude of file formats.
In a minimal approach you can update the current config file and add a new layer to it.
Alternatively you can create a new instance by duplicating the main pygeoapi service folder under a new name and update the main ansible orchestration to add the new service. Also you have to create a new file in https://github.com/Geonovum/ogc-api-testbed/tree/main/.github/workflows, having the new name. This tells github to (re)deploy the service when changes are detected. Note that INSPIRE mandates that each dataset is exposed via a unique service endpoint and pygeoapi can only provide a single service endpoint. Duplicating the deployment is then a usual approach.
Example of a pygeoapi collection
lakes: # name of the collection, e.g. /collection/lakes/items type: collection title: # title, keywords and description support multilingual en: Large Lakes nl: Grote meren description: lakes of the world, public domain keywords: - lakes crs: # CRS-es supported by backend - CRS84 links: # list of links to more info, for example metadata - type: text/html rel: canonical title: information href: http://www.naturalearthdata.com/ hreflang: en-US extents: # spatial and temporal extent of the layer spatial: bbox: [-180,-90,180,90] crs: http://www.opengis.net/def/crs/OGC/1.3/CRS84 temporal: begin: 2011-11-11 end: null # or empty providers: # list of backends - type: feature # service type (e.g. features, maps, styles, records, coverages) name: GeoJSON # type of provider (see docs for available types) data: tests/data/ne_110m_lakes.geojson # link to a file (or other provider specific configuration) id_field: id # field which contains the identifier title_field: name # field which contains the title of the element (can be multilingual)