docs: update install

docs/start/install.md

@@ -9,7 +9,7 @@ pip install sgl-kernel --force-reinstall --no-deps
 pip install "sglang[all]>=0.4.2.post4" --find-links https://flashinfer.ai/whl/cu124/torch2.5/flashinfer/
 ```
 
-Note: Please check the [FlashInfer installation doc](https://docs.flashinfer.ai/installation.html) to install the proper version according to your PyTorch and CUDA versions.
+Note: SGLang currently uses torch 2.5, so you need to install the flashinfer version for torch 2.5. If you want to install flashinfer separately, please refer to [FlashInfer installation doc](https://docs.flashinfer.ai/installation.html).
 
 ## Method 2: From source
 ```
@@ -22,7 +22,9 @@ pip install sgl-kernel --force-reinstall --no-deps
 pip install -e "python[all]" --find-links https://flashinfer.ai/whl/cu124/torch2.5/flashinfer/
 ```
 
-Note: Please check the [FlashInfer installation doc](https://docs.flashinfer.ai/installation.html) to install the proper version according to your PyTorch and CUDA versions.
+Note: SGLang currently uses torch 2.5, so you need to install the flashinfer version for torch 2.5. If you want to install flashinfer separately, please refer to [FlashInfer installation doc](https://docs.flashinfer.ai/installation.html).
+
+If you want to work on development in SGLang, it is highly recommended that you use docker. Please refer to [setup docker container](https://github.com/sgl-project/sglang/blob/main/docs/developer/development_guide_using_docker.md#setup-docker-container) for guidance. The image used is `lmsysorg/sglang:dev`.
 
 Note: To AMD ROCm system with Instinct/MI GPUs, do following instead: