Extend ClusterFuzzLite README

Signed-off-by: David Korczynski <[email protected]>

Author: DavidKorczynski

.clusterfuzzlite/README.md

@@ -1,4 +1,22 @@
 # ClusterFuzzLite set up
 
 This folder contains a fuzzing set for [ClusterFuzzLite](https://google.github.io/clusterfuzzlite).
-        
+
+
+## Running the fuzzer locally
+
+To reproduce the fuzzing by way of [OSS-Fuzz](https://github.com/google/oss-fuzz) (which ClusterFuzzLite will be using):
+
+```sh
+git clone https://github.com/google/oss-fuzz
+
+# Notice the destination folder shuold be in lower case.
+git clone https://github.com/FreeRTOS/coreJSON corejson
+cd corejson
+
+# Build the fuzzers in .clusterfuzzlite
+python3 ../oss-fuzz/infra/helper.py build_fuzzers --external $PWD
+
+# Run the fuzzer for 180 seconds
+python3 ../oss-fuzz/infra/helper.py run_fuzzer --external $PWD validate_fuzzer -- -max_total_time=180
+```