diff --git a/README.md b/README.md
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--- a/README.md
+++ b/README.md
@@ -1,3 +1,152 @@
+# Installation guide by Mauhing Yip
+# 1. Installation of ORB-SLAM 3 on a fresh installed Ubuntu 20.04
+Install all liberay dependencies.
+```shell
+
+sudo add-apt-repository "deb http://security.ubuntu.com/ubuntu xenial-security main"
+sudo apt update
+
+sudo apt-get install build-essential
+sudo apt-get install cmake git libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev
+
+sudo apt-get install python-dev python-numpy libtbb2 libtbb-dev libjpeg-dev libpng-dev libtiff-dev libdc1394-22-dev libjasper-dev
+
+sudo apt-get install libglew-dev libboost-all-dev libssl-dev
+
+sudo apt install libeigen3-dev
+
+```
+---
+
+### Install OpenCV 3.2.0
+The ORB-SLAM 3 was test by  
+```shell
+cd ~
+mkdir Dev && cd Dev
+git clone https://github.com/opencv/opencv.git
+cd opencv
+git checkout 3.2.0
+```
+Put the following at the top of header file `gedit ./modules/videoio/src/cap_ffmpeg_impl.hpp`  
+`#define AV_CODEC_FLAG_GLOBAL_HEADER (1 << 22)`  
+`#define CODEC_FLAG_GLOBAL_HEADER AV_CODEC_FLAG_GLOBAL_HEADER`  
+`#define AVFMT_RAWPICTURE 0x0020`  
+and save and close the file
+```shell
+mkdir build
+cd build
+cmake -D CMAKE_BUILD_TYPE=Release -D WITH_CUDA=OFF -D CMAKE_INSTALL_PREFIX=/usr/local ..
+make -j 3
+sudo make install
+```
+> If you want to install to conda environment, use `CMAKE_INSTALL_PREFIX=$CONDA_PREFIX` instead.
+---
+
+### Install Pangolin
+Now, we install the Pangolin. I used the commit version 86eb4975fc4fc8b5d92148c2e370045ae9bf9f5d
+```shell
+cd ~/Dev
+git clone https://github.com/stevenlovegrove/Pangolin.git
+cd Pangolin 
+mkdir build 
+cd build 
+cmake .. -D CMAKE_BUILD_TYPE=Release 
+make -j 3 
+sudo make install
+```
+> If you want to install to conda environment, add `CMAKE_INSTALL_PREFIX=$CONDA_PREFIX` instead.
+---
+
+### ORB-SLAM 3
+Now, we install ORB-SLAM3. I used the commit version ef9784101fbd28506b52f233315541ef8ba7af57 tag: v0.3-beta
+
+```shell
+cd ~/Dev
+git clone https://github.com/UZ-SLAMLab/ORB_SLAM3.git 
+cd ORB_SLAM3
+```
+We need to change the header file `gedit ./include/LoopClosing.h` at line 51  
+from  
+`Eigen::aligned_allocator<std::pair<const KeyFrame*, g2o::Sim3> > > KeyFrameAndPose;`  
+to  
+`Eigen::aligned_allocator<std::pair<KeyFrame *const, g2o::Sim3> > > KeyFrameAndPose;`
+in order to make this comiple.  
+Now, we can comiple ORB-SLAM3 and it dependencies as DBoW2 and g2o.  
+
+Now Simply just run (if you encounter compiler, try to run the this shell script 2 or 3 more time. It works for me.)
+```shell
+./build.sh
+```
+to install  
+
+---
+
+# 2. Download test datasets
+
+```shell
+cd ~
+mkdir -p Datasets/EuRoc
+cd Datasets/EuRoc/
+wget -c http://robotics.ethz.ch/~asl-datasets/ijrr_euroc_mav_dataset/machine_hall/MH_01_easy/MH_01_easy.zip
+mkdir MH01
+unzip MH_01_easy.zip -d MH01/
+
+```
+Similar for another datasets in EuRoc see here [https://projects.asl.ethz.ch/datasets/doku.php?id=kmavvisualinertialdatasets]
+
+
+# 3. Run simulation 
+```shell
+cd ~/Dev/ORB_SLAM3
+
+# Pick of them below that you want to run
+
+# Mono
+./Examples/Monocular/mono_euroc ./Vocabulary/ORBvoc.txt ./Examples/Monocular/EuRoC.yaml ~/Datasets/EuRoc/MH01 ./Examples/Monocular/EuRoC_TimeStamps/MH01.txt dataset-MH01_mono
+
+# Mono + Inertial
+./Examples/Monocular-Inertial/mono_inertial_euroc ./Vocabulary/ORBvoc.txt ./Examples/Monocular-Inertial/EuRoC.yaml ~/Datasets/EuRoc/MH01 ./Examples/Monocular-Inertial/EuRoC_TimeStamps/MH01.txt dataset-MH01_monoi
+
+# Stereo
+./Examples/Stereo/stereo_euroc ./Vocabulary/ORBvoc.txt ./Examples/Stereo/EuRoC.yaml ~/Datasets/EuRoc/MH01 ./Examples/Stereo/EuRoC_TimeStamps/MH01.txt dataset-MH01_stereo
+
+# Stereo + Inertial
+./Examples/Stereo-Inertial/stereo_inertial_euroc ./Vocabulary/ORBvoc.txt ./Examples/Stereo-Inertial/EuRoC.yaml ~/Datasets/EuRoc/MH01 ./Examples/Stereo-Inertial/EuRoC_TimeStamps/MH01.txt dataset-MH01_stereoi
+```
+
+# 4 Validation Estimate vs Ground True
+We need numpy and matplotlib installed in pytho2.7. But Ubuntu20.04 has not pip2.7
+```shell
+sudo apt install curl
+cd ~/Desktop
+curl https://bootstrap.pypa.io/2.7/get-pip.py --output get-pip.py
+sudo python2 get-pip.py
+pip2.7 install numpy matplotlib
+```
+
+**Run and plot Ground true**
+```
+cd ~/Dev/ORB_SLAM3
+
+./Examples/Stereo/stereo_euroc ./Vocabulary/ORBvoc.txt ./Examples/Stereo/EuRoC.yaml ~/Datasets/EuRoc/MH01 ./Examples/Stereo/EuRoC_TimeStamps/MH01.txt dataset-MH01_stereo
+```
+
+**Plot estimate vs Ground true**
+```
+cd ~/Dev/ORB_SLAM3
+
+python evaluation/evaluate_ate_scale.py evaluation/Ground_truth/EuRoC_left_cam/MH01_GT.txt f_dataset-MH01_stereo.txt --plot MH01_stereo.pdf
+```
+
+open the pdf `MH01_stereo.pdf` and you see the 
+
+# 5 Some comments
+1. You should download more datasets from EuRoc to see more 
+
+2. The support of inertial measurement unit (IMU) has incredibally increse the accuracy although it is alreday very accurate without IMU.
+
+# The rest is the original information
+
 # ORB-SLAM3
 
 ### V0.3: Beta version, 4 Sep 2020