[Enhance]: update installation docs (#189)

* update doc

* resolve comments

docs/backends/onnxruntime.md

@@ -29,6 +29,17 @@ export ONNXRUNTIME_DIR=$(pwd)
 export LD_LIBRARY_PATH=$ONNXRUNTIME_DIR/lib:$LD_LIBRARY_PATH
 ```
 
+Note:
+
+- If you want to save onnxruntime env variables to bashrc, you could run
+
+    ```bash
+    echo '# set env for onnxruntime' >> ~/.bashrc
+    echo "export ONNXRUNTIME_DIR=${ONNXRUNTIME_DIR}" >> ~/.bashrc
+    echo 'export LD_LIBRARY_PATH=$ONNXRUNTIME_DIR/lib:$LD_LIBRARY_PATH' >> ~/.bashrc
+    source ~/.bashrc
+    ```
+
 #### Build on Linux
 
 ```bash
@@ -46,7 +57,7 @@ make -j10
 ### List of supported custom ops
 
 | Operator                                                                     | CPU | GPU | MMDeploy Releases |
-| :----------------------------------------------------: | :---: | :---: | :-----------: |
+|:-----------------------------------------------------------------------------|:---:|:---:|:------------------|
 | [RoIAlign](../ops/onnxruntime.md#roialign)                                   |  Y  |  N  | master            |
 | [grid_sampler](../ops/onnxruntime.md#grid_sampler)                           |  Y  |  N  | master            |
 | [MMCVModulatedDeformConv2d](../ops/onnxruntime.md#mmcvmodulateddeformconv2d) |  Y  |  N  | master            |

docs/backends/tensorrt.md

@@ -6,7 +6,19 @@
 
 Please install TensorRT 8 follow [install-guide](https://docs.nvidia.com/deeplearning/tensorrt/install-guide/index.html#installing).
 
-**Note**: `pip Wheel File Installation` is not supported yet in this repo.
+**Note**:
+
+- `pip Wheel File Installation` is not supported yet in this repo.
+- We strongly suggest you install TensorRT through [tar file](https://docs.nvidia.com/deeplearning/tensorrt/install-guide/index.html#installing-tar)
+- After installation, you'd better add TensorRT environment variables to bashrc by:
+
+    ```bash
+    cd ${TENSORRT_DIR} # To TensorRT root directory
+    echo '# set env for TensorRT' >> ~/.bashrc
+    echo "export TENSORRT_DIR=${TENSORRT_DIR}" >> ~/.bashrc
+    echo 'export LD_LIBRARY_PATH=$TENSORRT_DIR/lib:$TENSORRT_DIR' >> ~/.bashrc
+    source ~/.bashrc
+    ```
 
 #### Build custom ops
 

docs/build.md

@@ -1,15 +1,41 @@
-## Build MMdeploy
+## Build MMDeploy
+
+### Preparation
+
+- Download MMDeploy
+
+    ```bash
+    git clone -b master git@github.com:grimoire/deploy_prototype.git MMDeploy
+    cd MMDeploy
+    git submodule update --init --recursive
+    ```
+
+    Note:
+
+  - If fetching submodule fails, you could get submodule manually by following instructions:
+
+      ```bash
+      git clone git@github.com:NVIDIA/cub.git third_party/cub
+      cd third_party/cub
+      git checkout c3cceac115
+      ```
+
+- Install cmake
+
+    Install cmake>=3.14.0, you could refer to [cmake website](https://cmake.org/install) for more detailed info.
+
+    ```bash
+    apt-get install -y libssl-dev
+    wget https://github.com/Kitware/CMake/releases/download/v3.20.0/cmake-3.20.0.tar.gz
+    tar -zxvf cmake-3.20.0.tar.gz
+    cd cmake-3.20.0
+    ./bootstrap
+    make
+    make install
+    ```
 
 ### Build backend support
 
-Update third-party libraries.
-
-```bash
-git submodule update --init
-```
-
-Install cmake>=3.14.0
-
 Build the inference engine extension libraries you need.
 
 - [ONNX Runtime](backends/onnxruntime.md)
@@ -21,5 +47,6 @@ Build the inference engine extension libraries you need.
 ### Install mmdeploy
 
 ```bash
+cd ${MMDEPLOY_DIR} # To mmdeploy root directory
 pip install -e .
 ```