Update README

README.md

@@ -25,6 +25,14 @@ AmneziaVPN uses a number of open source projects to work:
 - [QtSsh](https://github.com/jaredtao/QtSsh) - forked form Qt Creator
 - and more...
 
+## Checking out the source code
+
+Make sure to pull all submodules after checking out the repo.
+
+```bash
+git submodule update --init
+```
+
 ## Development
 
 Want to contribute? Welcome!
@@ -34,6 +42,58 @@ Easiest way to build your own executables - is to fork project and configure [Tr
 Or you can build sources manually using Qt Creator. Qt >= 14.2 supported.  
 Look to the `build_macos.sh` and `build_windows.bat` scripts in `deploy` folder for details.
 
+### How to build iOS app from source code on MacOS
+
+1. First, make sure you have [XCode](https://developer.apple.com/xcode/) installed, 
+at least version 12 or higher.
+
+2. We use `qmake` to generate the XCode project and then we "patch" it to add
+extra components such as the wireguard, the browser bridge and so on. We patch
+the XCode project using [xcodeproj](https://github.com/CocoaPods/Xcodeproj). To
+install it:
+```bash
+gem install xcodeproj # probably you want to run this command with `sudo`
+```
+3. You also need to install go >= v1.16. If you don't have it done already,
+download go from the [official website](https://golang.org/dl/) or use Homebrew. 
+Latest version is recommended.
+
+4. Navigate inside client folder and generate the XCode project using our script:
+```bash
+cd client
+./scripts/apple_compile.sh ios
+```
+
+If you have more than one version of Qt installed, you'll most likely get
+a "`qmake` cannot be found in your `$PATH`" error. In this case run this script 
+using QT\IOS\_BIN env to set the path for the Qt5 macos build bin folder.
+For example, the path could look like this:
+```bash
+QT_IOS_BIN="/Users/username/Qt/5.15.2/ios/bin" ./scripts/apple_compile.sh ios
+```
+
+If you get `gomobile: command not found` make sure to set PATH to the location 
+of the bin folder where gomobile was installed. Usually, it's in `GOPATH`.
+```bash
+export PATH=$(PATH):/path/to/GOPATH/bin
+```
+
+5. Xcode should automatically open. You can then run/test/archive/ship the app.
+
+If build fails with the following error
+```
+make: *** 
+[$(PROJECTDIR)/client/build/AmneziaVPN.build/Debug-iphoneos/wireguard-go-bridge/goroot/.prepared] 
+Error 1
+```
+Add a user defined variable to both AmneziaVPN and WireGuardNetworkExtension targets' build settings with
+key `PATH` and value `${PATH}/path/to/bin/folder/with/go/executable`, e.g. `${PATH}:/usr/local/go/bin`.
+
+Build might fail with "source files not found" error the first time you try it, because modern XCode build system compiles
+dependencies in parallel, and some dependencies end up being built after the ones that
+require them. In this case simply restart the build.
+
+
 ## License
 GPL v.3