open-source-silicon.dev

can someone point me to a tutorial on how to use this?

How about <http://opencircuitdesign.com/magic/tutorials/>

I assume I would create a schematic in xschem or something, and then run simulation

Sounds good. I haven't tried that myself, though. Are you in the IEEE SSCS 2022 design contest?

I'm trying to build a fast function generator IC, and hopefully get it done before the deadline for the Google Silicon thing

<https://sscs.ieee.org/about/solid-state-circuits-directions/sscs-pico-design-contest>
Tim Edwards gave a presentation about using magic last week.
Good luck!