Whenever a transaction is added to a block, it receives 1 confirmation. If a block containing a Rob transaction is used, it means that the Rob transaction has 1 confirmation and the confirmation value increases by one each time a block is added to Blockchain thereafter. As if a block was added to the blockchain after the block in which Rob’s transaction was present, the transaction would have 2 confirmations. And if a block is added after this block, Rob’s transaction will have 3 confirmations, and this continues on and on. It is recommended to wait at least 6 confirmations to be 99.9% sure that your transaction will not be canceled – it takes about 1 hour.