When you believe a particular coin price will go down; you don't buy again, you short the trade which we refer to as sell. It's definitely not for everyone because of it high risk. It looks good in theory but a very dangerous strategy because once you short your trade and the market price start appreciating, is your money that is gradually liquidating as the price increases.

I think you should first of all learn about the basics of trading before even thinking of joining a signal group. I'm afraid you're likely to loose your money since you can not even tell or understand how buy and sell works in trading. Don't forget to switch your account to future trading before you begin else you might lose your money if you are on spot trading. It's important to be aware of the risks involved in trading before you attempt to get into it. Knowledge first, then practice follows.