How do I get cydia

If your iPad was properly jailbroken, Cydia is automatically installed on your device. If you do not see Cydia as one of the Apps, either it was never properly jailbroken or you accidentally deleted the app. In either case, go through the jailbreaking process again. Make sure your iOS version is supported by the jailbreak program.

Also, anytime you update your iOS version, you will lose your jailbreak. It's never a good idea to update iOS unless you know the new version is supported by the jailbreaking programs. Also, never update OTA (Over the Air) aka wirelessly. ALWAYS update your iOS by plugging your device into a computer and doing it through iTunes. Doing OTA updates sometimes has crippling effects.