This template will provision an ArcGIS Enterprise deployment that includes Portal for ArcGIS, a GIS Server site (set as the portal's hosting server), ArcGIS Data Store (which will create a relational and tile cache data store and you can optionally direct the template to create a spatiotemporal big data store), and ArcGIS Web Adaptor on one AWS instance. It will set up an architecture as shown in the graphic below.
See Troubleshoot AWS CloudFormation stack creation in the ArcGIS Enterprise on Amazon Web Services help if you run into problems.
The Portal for ArcGIS initial administrator needs to customize the portal for your organization's use. See the topics in the Portal for ArcGIS administrator guide for information on configuring the portal web site, adding members, securing the portal, and other administrative tasks.