You didn't give people much to go on, but there are some common issues.
The check valve in the squeeze bulb can have a hard time priming the first time if the ball and seat are dry, raising the tank and lowering the hose may help.
The arrow needs to point up on the squeeze bulb (already been mentioned).
All too frequently the Squeeze bulb won't work at all, even when new they can have issues. I just return them if I even suspect a problem.
Bad seal at the tank end.