Once you are ready to to send an operation to the network, you need to build a transaction. This will take all the pending operations and build a Stellar transaction from it.
You will need to specify the following
Transaction source: This defaults to the active wallet.
Memo(optional): An custom identifier for your transaction.
Fee: This is the network fee per operation.
Time bounds(optional): The period in which the transaction is valid.
Click on "Build" to build the transaction. If successful, you will then proceed to sign the transaction.