update main README to refer to PyPI

README.md

@@ -1,6 +1,6 @@
 # PETSIRD draft data model and examples
 
-The purpose of this repo is to have a simple working example of a data model for PET imaging (list mode data). This is **not complete**, and aspects do not follow the actual proposal of PETSIRD yet.
+The purpose of this repo is to have a working example of a data model for PET imaging (list mode data). This is **not complete**, and aspects do not follow the actual proposal of PETSIRD yet.
 
 ## Background
 
@@ -9,9 +9,13 @@ is working towards establishing a standard for PET Raw Data, called PETSIRD ("PE
 
 The specification uses the [yardl](https://aka.ms/yardl) tool to define the model.
 `yardl` can be used to read the specification (in the `model` directory) and
-generate an SDK for both C++ and API to read/write PETSIRD data.
+generate an SDK for both C++ and Python to read/write PETSIRD data.
 
-## To get started quickly:
+## To get started as a Python user:
+
+If you don't want to modify the yardl model, clone this repository and follow instructions in the [`python/README.md`](python/README.md).
+
+## To get started quickly as a developer:
 
 1. Open this repo in [GitHub Codespaces](https://code.visualstudio.com/docs/remote/codespaces) or
 in a [VS Code devcontainer](https://code.visualstudio.com/docs/devcontainers/containers).
@@ -26,3 +30,5 @@ This codespace/container will contain all necessary tools, including `yardl` its
 
 4. Have a look at (and try!) the examples in the [`cpp`](cpp/README.md) and/or
 [`python`](python/README.md) directories.
+
+