Am I complete idiot? How does 4e work?

[Knave of Spades]

Hey there! So I have been using HL for years, mostly for Pathfinder, Starfinder, 5e and Shadowrun.

I was feeling nostalgic and wanted to show mt friends 4e. However, I cannot seem to figure out how. Anytime I try to use 4e in HL I am stuck in demo mode, and essentially can't use the software for its purpose. I tried to purchase the data pack since that's the only hint it gives me to get it to work. However, I cannot find a 4e pack. Only an authoring kit in Savage Worlds.

Am I missing a very obvious way to use HL for 4e?