Well points can get clogged up, and you have to try to flush them clean by forcing water into them, to blow clogging particles away from the screen.
It's a repetitive process. You backflush. You let the pump draw water. You back flush. You pump. So on and so on.
What you are trying to achieve is to get as many small particles as possible into the well point and through the pump.
If you have a clear-body strainer on the pump outlet, like a Vu-Flow, you can tell when you are no longer bringing up extra particles through the pump.