Step 2: Hal research and uses every trick and exploits known to men to infiltrate critical infrastructures like telecommunications, power grids and private corporations of said country. Hal actively search and discover zero-day exploits on every known piece of hardware and software. Hal keeps mostly invisible at this stage, ensuring to leave as little trace as possible.
Step 3: When ready, Hal wreaks havoc, disabling critical infrastructures, shutting down power grid or worse, overloading it to break as many physical systems as possible. Hal complicates coordination by impersonating real people, swamp the infosphere with fake but realistic data.
This vould all be made by humans, but while a single human takes years to train, Hal can be replicated as much as needed.