You have the app yet you cannot do transactions using that app? What, have you imported a watch-only address? Upon downloading a wallet app, it comes with a private key already, even blockchain.info app has that. It might have been that you are using a wallet that is watch-only and cannot be used to spend coins, only receive coins and you cannot do anything to those coins being received, hence the term "watch-only".

Are there already coins in the address?