Quartz and the packages around it come from NuGet:

dotnet add package Quartz

That is the whole install for a scheduler — dependency injection, hosting, the health check and System.Text.Json serialization are in that package. The quick start lists the optional packages and what each one is for.

Each GitHub release also carries a Quartz.NET-<version>.zip with the source, the compiled binaries, the example projects and the database/ directory — the table-creation script and the migrations for every supported database. Those scripts are also readable in the repository, and what each migration changes is written up in schema changes.