Updated readme

README.md

@@ -107,3 +107,24 @@ If you have any questions, suggestions, ideas or just want to chat, feel free
 to post on the [forums](https://forum.uwyn.com) or to join  us on [Discord](https://discord.gg/zDG6anEXQX).
 
 Read more in the [full documentation](https://github.com/rife2/bld/wiki) and [bld Javadocs](https://rife2.github.io/bld/).
+
+# Building `bld`
+
+If you want to contribute to `bld` or customize it, all you have to do is clone the GitHub
+repository and update the [RIFE2/core](https://github.com/rife2/rife2-core) submodule:
+
+```bash
+git clone [email protected]:rife2/bld.git
+cd bld
+git submodule init
+git submodule update
+```
+
+Then use `bld` to build itself:
+
+```bash
+./bld compile
+```
+
+The project has an Intellij IDEA project structure. You can just open it after all
+the dependencies were downloaded and peruse the code.