diff --git a/README.md b/README.md
index aea0979..1b83b72 100644
--- a/README.md
+++ b/README.md
@@ -22,3 +22,18 @@ if (ANDROID)
     include(<path/to/android_openssl/CMakeLists.txt)
 endif()
 ```
+
+## Build Script
+
+The build script `build_ssl.sh` can be used to rebuild the OpenSSL libraries. Since specific
+versions might depend or work better with specific NDK versions, the OpenSSL<==>NDK version
+combinations are defined in the script. Before running the script, check that the NDK paths
+are correct for your environment.
+
+### Build Prerequisites
+
+Both Linux, macOS need `patchelf` command when building for OpenSSL 3+.
+
+Additionally, for macOS you need:
+- `bash` shell version 4+ is required
+- `wget` command
diff --git a/build_ssl.sh b/build_ssl.sh
index b0e7793..b0ac310 100755
--- a/build_ssl.sh
+++ b/build_ssl.sh
@@ -1,5 +1,11 @@
 #!/bin/bash
 
+## Prerequisites
+## On both Linux, macOS: 'patchelf' command is needed for OpenSSL 3+
+## On macOS:
+##   - bash shell version 4+ is required
+##   - wget command
+
 BUILD_DIR=$(pwd)
 
 # Comment out the line for any configuration you don't want to build