Please answer these questions:
1. Is it not connecting? Or dropping the connection?
2. Have you restarted your iPad?
3. Is the WIFI Password Correct? Click on the Blue arrow, choose forget network, and try to connect again.
4. What version of iOS is on this iPad?
5. What Generation iPad is this? 1, 2, 3, or 4?
This will give a little more insight into your problem. You've most likely put the password in wrong, or need to restart your ipad.