wont run only starts then dies after batt replacement

I may know what wrong, but first a question. Does the car have a security light that's blinking, it may be in your radio. If so the security may need reset to make it stay running.

if it is the immobilizer, in the dash there would be a car with a key blinking yellow. if not there is another problem. you need to read the codes... if you don't have a proper equipment to read the codes, do this first. disconnect the battery both cables and touch them together to discharge the parasite current and the car would reset some of the adaptations. connect negative and then positive terminals. and test. if the car starts you will need to adapt the throttle but this must be done with VAG equipment. come back if you need more help