3.7 Checkpoint: ready to build for real

Most of this module happened in windows and wizards, so this checkpoint is more checklist than command output. Two commands first, run on your host machine:

# The ISO shelf is stocked: Ubuntu Server and the Windows Server
# evaluation. (Kali is a VM, so it lives under VMs instead.)
# Windows PowerShell: use  ls C:\ISOs  and  ls C:\VMs
ls ~/ISOs
ls ~/VMs

# Disk reality check after the downloads: you still need room for
# the real VMs. df on Linux/mac; Get-PSDrive C on Windows.
df -h ~

Pass criteria

• The hypervisor installs and opens cleanly (lesson 3.2), and you know which one you're on for the rest of the course
• Folders exist and are used: installers in ISOs, one folder per machine under VMs, and neither is inside a synced folder like OneDrive (lesson 3.3)
• All three images are downloaded: Ubuntu Server LTS and the newest Windows Server evaluation ISO in ISOs, and the Kali prebuilt VM unpacked into its own folder under VMs (lesson 3.3)
• You verified the Ubuntu and Kali checksums against the vendor's published values, and you can say in one sentence what that proved and what the Microsoft download's assurance rests on instead (lesson 3.3)
• You can state when the Windows 180-day clock starts, and name the two reasons it shouldn't scare you (lesson 3.3)
• You built practice01 from the ISO, declined the automated install, and ticked OpenSSH during setup (lesson 3.4)
• You snapshotted it, destroyed /boot, watched it fail to start, and reverted it back to life (lesson 3.5)
• You then deleted the VM without ceremony, and you can explain "cattle, not pets" to someone in one breath (lesson 3.5)
• At least 100 GB of disk remains free for the permanent lab VMs
• Journal entry written, committed, pushed; Module 3 ticked in lab-progress.md (lesson 3.6)

All green? Then you can make computers now. Module 4 teaches the part you deferred today: what NAT was doing, where that IP came from, and how to wire multiple VMs into an actual network with an inside and an outside.