Update readme

Author: shaobin

README.md

@@ -30,7 +30,7 @@ slimmer. Some obsolete or outdated modules and tools have been moved to the
 
 ## Getting started
 
-Recommended operating system: Windows 10 or Ubuntu 20.04.
+Recommended operating system: Windows 10 or Ubuntu 22.04.
 
 ### Building on Windows
 
@@ -40,8 +40,8 @@ Download and install [Visual Studio][vs] with the following "workloads" and
 - The ".NET desktop development" and "Desktop development with C++" workloads.
 - The ".NET Portable Library targeting pack" individual component.
 
-Open a PowerShell window, run `tools/build.ps1` for building the NuGet packages.
-The script has been tested on Windows 10 (21H2) with Visual Studio 2022.
+Open a PowerShell window, run `.\tools\build.ps1` for building the NuGet packages.
+The script has been tested on Windows 10 (22H2) with Visual Studio 2022.
 
 ### Building on Linux
 
@@ -51,13 +51,15 @@ Install g++, cmake, and libssl-dev. For example, on Ubuntu, simply run
 sudo apt update && sudo apt install g++ cmake libssl-dev
 ```
 
-Install [.NET SDK x64 6.0][dotnet6-on-ubuntu20-04] and run:
+Install [.NET SDK x64 6.0][dotnet6-on-linux]. For example, on Ubuntu 22.04, run
+`sudo apt update && sudo apt install -y dotnet-sdk-6.0`.
+Then, build GraphEngine with the following command:
 
 ```shell
 bash tools/build.sh
 ```
 
-The build script has been tested on Ubuntu 20.04 with g++ 9.4.0.
+The build script has been tested on Ubuntu 22.04 with g++ 11.4.0.
 
 ### Using the built packages
 
@@ -121,6 +123,6 @@ Links
 
 [dotnet-download]: https://dotnet.microsoft.com/
 
-[dotnet6-on-ubuntu20-04]: https://docs.microsoft.com/en-us/dotnet/core/install/linux-ubuntu#2004
+[dotnet6-on-linux]: https://dotnet.microsoft.com/en-us/download/dotnet/6.0
 
 [license]: LICENSE.md