Meaning that before hopping onto a particular signal/ signals, you should already have a personal strategy or signal on ground which will then be used to compare with the signal you got to know if you are right on track.
If you already have your own strategy, traders don't need signals. Traders who use signals are often those who lack a strategy or are lazy about learning to analyze, simply seeking quick profits, which isn't always successful.
You can get signals by joining a group, and most of these groups are scams, whether free or paid.
Keep learning to improve your skills, rather than relying on others.