update README

README.md

@@ -12,16 +12,30 @@ pip install -r requirements.txt
 ### Runnning
 
 ```shell
+lrelease ./lang/*.ts # Generate ./lang/*.qm files
 python app.py
 ```
+`lrelease` is shipped with Qt. You can find it in the Qt installation directory. e.g.
+```
+C:\Qt\Qt5.14.2\5.14.2\mingw73_64\bin\lrelease.exe
+```
+
+If you don't want to install Qt, you can get *.qm files from our latest release. Download the zip file and extract it, *qm files are in the `lang/` folder.
+
 
 ### I18n
 
-To help with the translation, do the following:
+To help with the translation, do the following steps.
+
+First run pylupdate5 to update the .ts files.
 
 ```shell
 pylupdate5 app.py -ts ./lang/*.ts
-# Manually edit the ts file you want to translate. e.g. ./lang/zh_CN.ts
+```
+Then manually edit the ts file you want to translate. e.g. ./lang/zh_CN.ts
+
+Finally use Qt’s lrelease utility to convert the .ts files to .qm files.
+```shell
 lrelease ./lang/*.ts
 ```