One of the reasons people choose a full-service broker is because they can offer personal guidance on how to invest money, BUT you already know how to do that, and your broker isn’t necessarily going to follow the same strategy you want to.
In addition to choosing your online broker, the type of investment you want to make, and the amount of money you will invest, you also have to decide the type of order you will place when you purchase the stock.
If you set a limit order at the “buy price” that you have determined for a specific stock, then the brokerage will execute the order for you when the time is right, so you don’t have to constantly keep your pulse on the stock price.
When you’re ready to sell, simply go into your brokerage account and place a sell order for the shares you want to sell.