diff --git a/docs/dev/api_quickstart.md b/docs/dev/api_quickstart.md
new file mode 100644
index 00000000..7b33a1ab
--- /dev/null
+++ b/docs/dev/api_quickstart.md
@@ -0,0 +1,73 @@
+# API Quick Start
+
+
+The preview of the Validation Service API is available at `https://dev.validate.buildingsmart.org/api`.
+
+## Documentation
+
+Auto-generated documentation is available in both
+[Swagger](https://dev.validate.buildingsmart.org/api/swagger-ui)
+and
+[Redocly](https://dev.validate.buildingsmart.org/api/redoc)
+formats.
+
+## Auth token
+
+You will need an Authentication token before making calls to the API,
+which can be obtained by emailing [validate@buildingsmart.org](mailto:validate@buildingsmart.org).
+
+You can use this token either as a Bearer token or use it as the password in combination with your username/email for basic authentication.
+
+## Example usage
+
+1. Sample to show difference between Token vs. Basic authentication
+
+    ``` shell
+     curl -X GET --location 'https://dev.validate.buildingsmart.org/api/validationrequest/' --header 'Authorization: Token <TOKEN>'
+    ```
+
+   -or-
+
+    ```shell
+    curl -X GET --location 'https://dev.validate.buildingsmart.org/api/validationrequest/' --header 'Authorization: Basic <HASH>'
+    ```
+
+   where `<HASH>` is the Base64-encoded email and token as password, separated by a colon, eg. base64(johndoe@gmail.com:abcdefgh12345)
+
+2. Submit a POST request to the `/validationrequest` endpoint to initiate a new Validation Request (requires a file name and the file contents):
+
+   ```shell
+      curl -X POST --location 'https://dev.validate.buildingsmart.org/api/validationrequest/' \
+
+      --header 'Authorization: Token <TOKEN>' \
+
+      --form 'file_name="valid_file.ifc"' \
+
+      --form 'file=@"/.../buildingSMART/sample_files/valid_file.ifc"'
+   ```
+
+   It will return a JSON object that includes the id (public_id) you can use for future GET requests.
+
+3. Fetch details of a single ValidationRequest via a GET request to the `/validationrequest` endpoint
+
+   ```shell
+      curl -X GET --location 'https://dev.validate.buildingsmart.org/api/validationrequest/r767775526' --header 'Authorization: Token <TOKEN>'
+   ```
+
+4. Fetch details of all ValidationRequests via a GET request to the `/validationrequest` endpoint
+
+   ```shell
+   curl -X GET --location 'https://dev.validate.buildingsmart.org/api/validationrequest/' --header 'Authorization: Token <TOKEN>'
+   ```
+
+5. Fetch all ValidationTasks for two ValidationRequests via a GET request to the `/validationtask` endpoint
+
+   ```shell
+   curl -X GET --location 'https://dev.validate.buildingsmart.org/api/validationtask/?request_public_id=r75257132,r383446691' --header 'Authorization: Token <TOKEN>'
+   ```
+
+6. Fetch all the outcomes of a single ValidationRequest via a GET request to the `/validationoutcome` endpoint
+
+   ```shell
+   curl -X GET --location 'https://dev.validate.buildingsmart.org/api/validationoutcome/?request_public_id=r75257132' --header 'Authorization: Token <TOKEN>'
+   ```
diff --git a/docs/dev/ifc_gherkin_rules_readme.md b/docs/dev/ifc_gherkin_rules_readme.md
index b4f42f09..244ed755 100644
--- a/docs/dev/ifc_gherkin_rules_readme.md
+++ b/docs/dev/ifc_gherkin_rules_readme.md
@@ -9,7 +9,7 @@ An overview of the implemented rules and python step implementation functions is
 
 ## Making changes
 
-The rules developed in this repository follow the general ideas of Gherkin and its python implementation behave.
+The rules developed in this repository follow the general ideas of Gherkin and its python implementation [behave](https://behave.readthedocs.io/en/stable/).
 
 This means there are human-readable definitions of rules and Python implementations.
 
diff --git a/docs/dev/index.md b/docs/dev/index.md
index 3e3e42b5..c0c01d41 100644
--- a/docs/dev/index.md
+++ b/docs/dev/index.md
@@ -4,6 +4,10 @@
 :heading-offset: 1
 ```
 
+```{include} api_quickstart.md
+:heading-offset: 1
+```
+
 ```{include} ifc_gherkin_rules_readme.md
 :heading-offset: 1
 ```
diff --git a/docs/ref/index.md b/docs/ref/index.md
index 9c4e7b25..35ebc2d7 100644
--- a/docs/ref/index.md
+++ b/docs/ref/index.md
@@ -35,3 +35,8 @@ The responses to these inquiries are provided here for the benefit of the entire
 :heading-offset: 1
 :relative-images:
 ```
+
+```{include} ./normative-rules/BRP003.md
+:heading-offset: 1
+:relative-images:
+```
diff --git a/docs/ref/normative-rules/BRP003.md b/docs/ref/normative-rules/BRP003.md
new file mode 100644
index 00000000..d6c2748b
--- /dev/null
+++ b/docs/ref/normative-rules/BRP003.md
@@ -0,0 +1,13 @@
+# BRP003
+
+This rule confirms that geometric faces indicated as being planar
+do actually lie on the same plane.
+
+## Approach
+
+1. Derive the plane from the outer boundary; uses Newell’s method for the normal and compute d from the average of the input points.
+2. Validate outer and inner boundaries by projecting their points onto that plane and checking that each projection distance is within the representation context precision.
+
+```{note}
+All calculations are performed in 128-bit floating point.
+```