Only have the classic rules showing up in Foundry VTT

[Finnerd]

New to running Foundry VTT. The classic game seems to be contained in the classic module, but the advanced features are missing despite the game system being applied to the world I have created. Clearly, I am missing something. Is there an advanced compendium there which I need contained in a module like the classic game?
If I could get a "Step 1: go to here, click this. Step 2 do this" etc.
Thanks for any help

[JordanRR]

Unfortunately, from what I gather, the advanced modules only contain compendium information (like spells, classes, races, etc.) The system itself is not modified (so no separate race and class, for example).