Document how to change the kernel config of microdroid kernels

Bug: 254927882
Test: N/A
Change-Id: Ie14256695b36ef20c3856e7cc83888e8151a6041
diff --git a/microdroid/kernel/README.md b/microdroid/kernel/README.md
index 1f6b2ee..38eca71 100644
--- a/microdroid/kernel/README.md
+++ b/microdroid/kernel/README.md
@@ -24,6 +24,7 @@
 
 For x86\_64,
 ```bash
+tools/bazel clean
 tools/bazel run --config=fast --lto=thin //common-modules/virtual-device:microdroid_x86_64_dist -- --dist_dir=out/dist
 ```
 
@@ -36,7 +37,15 @@
 
 ### Change the kernel configs
 
+For ARM64
+```bash
+tools/bazel run //common-modules/virtual-device:microdroid_aarch64_config menuconfig
+```
 
+For x86\_64
+```bash
+tools/bazel run //common-modules/virtual-device:microdroid_x86_64_config menuconfig
+```
 
 ## How to update Microdroid kernel prebuilts