docs: add Docker quickstart for gcd on nangate45

Add a short verified walkthrough for the default ORFS smoke test and fix
the GDS output path in index.md to include the base flow variant.

Signed-off-by: fusang <fusang991@gmail.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

Author: fusang991-glitch

docs/index.md

@@ -120,9 +120,10 @@ make
 
 By default, the `gcd` design is selected using the
 `nangate45` platform. The resulting GDS will be available at
-`flow/results/nangate45/gcd/6_final.gds`. The flow should take only a few
+`flow/results/nangate45/gcd/base/6_final.gds`. The flow should take only a few
 minutes to produce a GDS for this design. We recommend implementing this
-design first to validate your flow and tool setup.
+design first to validate your flow and tool setup. For a minimal Docker-only
+walkthrough, see the [gcd quickstart](tutorials/QuickstartGcdNangate45.md).
 
 ### Design exploration and automatic parameter tuning
 

docs/toc.yml

@@ -45,6 +45,8 @@ entries:
 - file: tutorials/TutorialHome
   title: Tutorials
   entries:
+  - file: tutorials/QuickstartGcdNangate45
+    title: "Quickstart: gcd on nangate45 (Docker)"
   - file: tutorials/FlowTutorial
     title: Flow Tutorial
   - file: tutorials/Notebooks

docs/tutorials/QuickstartGcdNangate45.md

@@ -0,0 +1,114 @@
+# Quickstart: Run gcd on nangate45 with Docker
+
+This guide runs the smallest ORFS smoke test ¡ª the `gcd` design on the
+`nangate45` platform ¡ª from RTL to GDS using the pre-built Docker image.
+No local compilation is required.
+
+For the full RTL-to-GDS walkthrough with interactive examples, see the
+[Flow Tutorial](FlowTutorial.md).
+
+## Prerequisites
+
+- Docker installed and running (Docker Desktop with WSL integration on Windows)
+- At least 1 CPU core and 8 GB RAM (4 cores recommended)
+- A clone of [OpenROAD-flow-scripts](https://github.com/The-OpenROAD-Project/OpenROAD-flow-scripts)
+
+## One-time setup: pull the Docker image
+
+Downloading the image is separate from running the flow. Do this once:
+
+```shell
+docker pull openroad/orfs:latest
+```
+
+## Run the flow
+
+From the root of your `OpenROAD-flow-scripts` clone:
+
+```shell
+cd flow
+util/docker_shell make
+```
+
+The `Makefile` defaults to `DESIGN_CONFIG=./designs/nangate45/gcd/config.mk`,
+so no extra flags are needed for this quickstart.
+
+To select the design explicitly:
+
+```shell
+util/docker_shell make DESIGN_CONFIG=./designs/nangate45/gcd/config.mk
+```
+
+On success, `make` prints a stage summary table at the end. For `gcd`, the
+total runtime is typically **under five minutes** on a modern machine. A full
+clean run on WSL2 with Docker Desktop completed in about one minute in our
+verification (see [Verified environment](#verified-environment) below).
+
+## Expected output
+
+Final layout files are written under the `base` flow variant:
+
+| Artifact | Path |
+|----------|------|
+| GDSII | `flow/results/nangate45/gcd/base/6_final.gds` |
+| DEF | `flow/results/nangate45/gcd/base/6_final.def` |
+| Logs | `flow/logs/nangate45/gcd/base/` |
+
+Confirm the GDS exists:
+
+```shell
+ls -lh results/nangate45/gcd/base/6_final.gds
+```
+
+## Optional: view the layout in the GUI
+
+If you have an X11 display available (for example, WSLg on Windows 11):
+
+```shell
+util/docker_shell make gui_final
+```
+
+This opens the finished layout in the OpenROAD GUI. It is not required to
+validate that the flow completed successfully.
+
+## Troubleshooting
+
+### `xauth` warnings when running headless
+
+When no graphical display is available, `util/docker_shell` may print `xauth`
+warnings. These can be ignored for `make`; they do not affect RTL-to-GDS
+execution.
+
+### Image not found
+
+If Docker reports that `openroad/orfs:latest` is missing, run:
+
+```shell
+docker pull openroad/orfs:latest
+```
+
+### Re-running from scratch
+
+To remove previous results for this design and run all stages again:
+
+```shell
+util/docker_shell make clean_all
+util/docker_shell make
+```
+
+## Next steps
+
+- Read the [Flow Tutorial](FlowTutorial.md) for stage-by-stage exploration
+- See [Docker Shell](../user/DockerShell.md) for other `docker_shell` options
+- See [Adding New Designs](../user/AddingNewDesign.md) to bring your own RTL
+
+## Verified environment
+
+This quickstart was verified with:
+
+- OS: WSL2 (Linux)
+- Docker: Docker Desktop 28.4.0
+- Image: `openroad/orfs:latest`
+- Command: `util/docker_shell make DESIGN_CONFIG=./designs/nangate45/gcd/config.mk`
+- Full clean run (`make clean_all` then `make`): ~61 seconds wall time
+- Output: `flow/results/nangate45/gcd/base/6_final.gds` present

docs/tutorials/TutorialHome.md

@@ -1,5 +1,8 @@
 # OpenROAD-flow-scripts tutorial
 
+New users can run the smallest smoke test in a few minutes with Docker:
+[Quickstart: gcd on nangate45](QuickstartGcdNangate45.md).
+
 The links to the main flow tutorial, where we go through each step of 
 the RTL-GDSII flow are as [follows](FlowTutorial.md). We have also provided
 Google Colab packaging for ease of experimentation [here](Notebooks.md).