GH-538 - Add build steps documentation.

Author: mothmane

readme.adoc

@@ -107,6 +107,31 @@ Find the reference documentation link:{docs}[here].
 
 https://help.github.com/articles/creating-a-pull-request[Pull requests] are welcome. Note, that we expect everyone to follow the https://github.com/spring-projects/.github/blob/main/CODE_OF_CONDUCT.md[code of conduct].
 
+=== What you will need
+
+* Git
+* Java 17 or higher
+* Docker version 1.6.0 or higher
+
+=== Get the Source Code
+
+Clone the repository
+
+[source,bash]
+----
+git clone [email protected]:spring-projects/spring-modulith.git
+cd spring-modulith
+----
+
+=== Build the code
+
+To compile, test, and build
+
+[source,bash]
+----
+./mvnw -B
+----
+
 == License
 Spring Modulith is Open Source software released under the
 https://www.apache.org/licenses/LICENSE-2.0.html[Apache 2.0 license].