Arduino Uno ground pin to ESC ground. Arduino Uno pin 11 to ESC signal. Power Arduino with USB. Make sure COM port is connected. Download and extract BLHeliSuite16714903.zip from https://github.com/bitdump/BLHeli or https://www.mediafire.com/folder/dx6kfaasyo24l/BLHeliSuite. Run BLHeliSuite.exe
Make interfaces, select board, baud, port, and click Arduino BLHeli Bootload. Hit yes and stuff. Should see success.
Select ATMEL / SILABS Interface - USB/COM.
Select SiLabs ESC Setup tab and select COM port at the bottom-left. Hit Read Setup.