refactor: fix incomplete option documentation

Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
Change-Id: I529207118901eb68bdf3097e29c80a82618a415b
diff --git a/README.md b/README.md
index b71e918..4a283d3 100644
--- a/README.md
+++ b/README.md
@@ -82,13 +82,13 @@
 **To build the library with SHA384 support:**
 
 ```bash
-cmake -DHASH_ALGORITHM=SHA324 ..
-make
+CC=aarch64-none-elf-gcc cmake -B build -DHASH_ALGORITHM=SHA384 -DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY
+cmake --build build
 ```
 
 **To build the library with default SHA256:**
 
 ```bash
-cmake ..
-make
+CC=aarch64-none-elf-gcc cmake -B build -DHASH_ALGORITHM=SHA256 -DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY
+cmake --build build
 ```