The lab turns IPv4 forwarding off and makes sure vm.swappiness isn't 10. It adds two linked network interfaces, lab0 and lab1, which come back at every boot; NetworkManager and networkd leave them alone. The dummy module is unloaded. Reboot when a task says so; the check looks at the running system.

Tasks

Turn on IPv4 forwarding until the next reboot only. Check it yourself: sysctl net.ipv4.ip_forward shows 1 now and 0 after a reboot. Do this one before task 2.
Make IPv4 forwarding permanent, and set vm.swappiness to 10, in a file named /etc/sysctl.d/90-lab.conf, without rebooting.
Disable IPv6 on interface lab0 only, persistently. After a reboot, lab0 has no IPv6 addresses while lab1 and the other interfaces keep theirs.
Add the boot parameter audit=1 to every installed kernel, then reboot.
Make the dummy module load at every boot with two devices, then reboot. ip -br link | grep -c dummy should print 2.

Hints

sysctl -w, /proc/sys.
A .conf file in /etc/sysctl.d/, then sysctl --system.
Per-interface keys look like net.ipv6.conf.NAME.disable_ipv6.
grubby on RHEL relatives; /etc/default/grub and update-grub on Ubuntu. /proc/cmdline after the reboot.
modinfo -p dummy, /etc/modprobe.d/, /etc/modules-load.d/. Files in every modprobe.d directory are read in name order and the last setting wins; modprobe --show-depends dummy shows what modprobe will pass.