Inform the media: While it's essential to inform the media and the public, doing so should come after the incident has been contained and properly assessed. Sharing premature or inaccurate information could lead to confusion and further issues. 

Conduct root cause analysis: Understanding the root cause of the breach is vital for preventing future incidents, but this often takes time and should come after immediate containment measures have been put in place. 

Contain the incident: Containment is generally the first step after identifying a breach. It involves taking immediate action to stop unauthorized activity, such as isolating affected systems from the network, revoking access credentials, or shutting down certain services. This is critical to limit the damage and scope of the breach. 

Inform affected clients: Notifying affected parties is a legal and ethical requirement, but it generally comes after containment and assessment. You'll need to know the scope and impact of the breach to inform affected parties accurately.