You described it all wrong. Trading signals are groups that are leaded by bunch of scammers that are willing to scam all the people on their group. Those "signal givers" are the ones that makes all the money, while most of the people at the bottom loses everything. They give "signals" to pump low volume coins so that they can dump. They are the first one to dump, make all the profit, while others that are late loses all the money.
In other words,
1. The name of the coin the group leader wants to pump

2. The price to buy which keeps on increasing until the leaders desired profit goal is reached

3. The price to sell right after the leaders dump their profit on their followers