Update README.md

Author: jerryneedell

README.md

@@ -38,8 +38,9 @@ clone the Adafruit Repostitory to somewhere on your local machine.
 git clone https://github.com/adafruit/BOSSA.git
 change to the arduino branch
 git checkout arduino
-Follow the instructions to build bossac.
 ```
+Follow the instructions to build bossac inn README.md or at https://github.com/adafruit/BOSSA/tree/arduino.
+
 11. Replace the binary at ".../Library/Arduino15/packages/arduino/tools/bossac/1.7.0/bossac" or "...\AppData\Local\Arduino15\packages\arduino\tools\bossac\1.7.0\bossac"
 12. On Windows 7 you will also need to install the updated serial driver, download https://github.com/adafruit/Adafruit_Windows_Drivers/archive/master.zip to get all the drivers, and point the Device Manager to the unzipped folder. It isn't signed, so just approve the installation manually.
 13. That's it!