Open a margin account with a broker that allows short selling
Confirm that the stock is available to borrow
Place a short sell order for the stock
Sell the borrowed shares at the current market price
Wait for the stock price to decline
Buy back the same number of shares at the lower price
Return the borrowed shares to the lender
Keep the difference between the sell price and the buyback price, minus fees and interest
Monitor margin requirements and maintain sufficient collateral
Be aware that losses can be unlimited if the stock price rises