diff --git a/README.md b/README.md
index ab0195fd..50c33b0c 100644
--- a/README.md
+++ b/README.md
@@ -178,9 +178,10 @@ instructions for other platforms, and just in general, we recommend you see [Ras
       For example, if not using an IDE:
       ```
       $ cmake -S . -B build
-      ```   
+      ```
+      > The cmake -S flag indicates the source directory, and -B tells cmake where to put the output files.
    
-   When building for a board other than the Raspberry Pi Pico, you should pass `-DPICO_BOARD=board_name` to the `cmake` command above, e.g. `cmake -DPICO_BOARD=pico2 ..` or `cmake -DPICO_BOARD=pico_w ..` to configure the SDK and build options accordingly for that particular board.
+   When building for a board other than the Raspberry Pi Pico, you should pass `-DPICO_BOARD=board_name` to the `cmake` command above, e.g. `cmake -S . -B build -DPICO_BOARD=pico2` or `cmake -S . -B build -DPICO_BOARD=pico_w` to configure the SDK and build options accordingly for that particular board.
 
    Specifying `PICO_BOARD=<boardname>` sets up various compiler defines (e.g. default pin numbers for UART and other hardware) and in certain 
    cases also enables the use of additional libraries (e.g. wireless support when building for `PICO_BOARD=pico_w`) which cannot