diff --git a/changelog.d/15022.doc b/changelog.d/15022.doc
new file mode 100644
index 000000000..e1627c20c
--- /dev/null
+++ b/changelog.d/15022.doc
@@ -0,0 +1 @@
+Document how to start Synapse in the contributing guide.
diff --git a/docs/development/contributing_guide.md b/docs/development/contributing_guide.md
index 36bc88468..925dcd893 100644
--- a/docs/development/contributing_guide.md
+++ b/docs/development/contributing_guide.md
@@ -78,6 +78,19 @@ poetry install --extras all
 
 This will install the runtime and developer dependencies for the project.
 
+## Running Synapse via poetry
+
+To start a local instance of Synapse in the locked poetry environment, create a config file:
+
+```sh
+cp docs/sample_config.yaml homeserver.yaml
+```
+
+Now edit homeserver.yaml, and run Synapse with:
+
+```sh
+poetry run python -m synapse.app.homeserver -c homeserver.yaml
+```
 
 # 5. Get in touch.