Hello Toxamax, Thanks a lot for your reply.
But this collateral money is that my ticket and his money, or my ticket plus money and his money?
Only that part is unclear.
Thanks!!

Neither. You both chip in aditional money. That money will be held hostage until both parties have got what they wanted. A smart contract only starts when both parties have 'locked in' the required amount of money.
Once the contract is completed the funds will be restored back to the both of you again.
https://www.youtube.com/watch?v=-qGxYmtdrH4Hi Toxamax, thanks again for explaining.