Add tooling install instructions to contributor guide

{{cookiecutter.project_name}}/CONTRIBUTING.md

@@ -11,11 +11,6 @@ Here is a list of important resources for contributors:
 - [Issue Tracker]
 - [Code of Conduct]
 
-[{{cookiecutter.license.replace("-", " ").lower()}} license]: https://opensource.org/licenses/{{cookiecutter.license}}
-[source code]: https://github.com/{{cookiecutter.github_organization}}/{{cookiecutter.project_name}}
-[documentation]: https://{{cookiecutter.github_organization}}.github.io/{{cookiecutter.project_name}}
-[issue tracker]: https://github.com/{{cookiecutter.github_organization}}/{{cookiecutter.project_name}}/issues
-
 ## How to report a bug
 
 Report bugs on the [Issue Tracker].
@@ -43,50 +38,69 @@ You need Python 3.9+ and the following tools:
 - [Nox]
 - [nox-poetry]
 
-Install the package with development requirements:
+Install [pipx]:
 
 ```console
-$ poetry install
+python -m pip install --user pipx
+python -m pipx ensurepath
 ```
 
-You can now run an interactive Python session,
-or the command-line interface:
+Install [Poetry]:
 
 ```console
-$ poetry run python
-$ poetry run {{cookiecutter.project_name}}
+pipx install poetry
 ```
 
-[poetry]: https://python-poetry.org/
-[nox]: https://nox.thea.codes/
-[nox-poetry]: https://nox-poetry.readthedocs.io/
+Install [Nox] and [nox-poetry]:
+
+```console
+pipx install nox
+pipx inject nox nox-poetry
+```
+
+Install the pre-commit hooks
+
+```console
+nox --session=pre-commit -- install
+```
+
+Install the package with development requirements:
+
+```console
+poetry install
+```
+
+You can now run an interactive Python session, or your app:
+
+```console
+poetry run python
+poetry run {{cookiecutter.project_name}}
+```
 
 ## How to test the project
 
 Run the full test suite:
 
 ```console
-$ nox
+nox
 ```
 
 List the available Nox sessions:
 
 ```console
-$ nox --list-sessions
+nox --list-sessions
 ```
 
 You can also run a specific Nox session.
 For example, invoke the unit test suite like this:
 
 ```console
-$ nox --session=tests
+nox --session=tests
 ```
 
 Unit tests are located in the _tests_ directory,
 and are written using the [pytest] testing framework.
 
-[pytest]: https://pytest.readthedocs.io/
-
 ## How to submit changes
 
 Open a [pull request] to submit changes to this project.
@@ -102,12 +116,21 @@ Feel free to submit early, though—we can always iterate on this.
 To run linting and code formatting checks before committing your change, you can install pre-commit as a Git hook by running the following command:
 
 ```console
-$ nox --session=pre-commit -- install
+nox --session=pre-commit -- install
 ```
 
 It is recommended to open an issue before starting work on anything.
 This will allow a chance to talk it over with the owners and validate your approach.
 
+[{{cookiecutter.license.replace("-", " ").lower()}} license]: https://opensource.org/licenses/{{cookiecutter.license}}
+[source code]: https://github.com/{{cookiecutter.github_organization}}/{{cookiecutter.project_name}}
+[documentation]: https://{{cookiecutter.github_organization}}.github.io/{{cookiecutter.project_name}}
+[issue tracker]: https://github.com/{{cookiecutter.github_organization}}/{{cookiecutter.project_name}}/issues
+[pipx]: https://pipx.pypa.io/
+[poetry]: https://python-poetry.org/
+[nox]: https://nox.thea.codes/
+[nox-poetry]: https://nox-poetry.readthedocs.io/
+[pytest]: https://pytest.readthedocs.io/
 [pull request]: https://github.com/{{cookiecutter.github_organization}}/{{cookiecutter.project_name}}/pulls
 
 <!-- github-only -->