On some systems, Frost's Vulkan build won't launch correctly out of the box — usually showing up as a crash right on startup, or the game getting stuck on a black screen. This happens because of how certain GPU drivers expose Vulkan support to Java, and it isn't something that can be detected or fixed automatically. The fix is to manually add a few Java arguments to your instance in the Modrinth App.
Copy these three arguments — you'll paste them into the Modrinth App in the next step.
In the Modrinth App, go to your Library and click on your Frost instance to open it.
Click the gear/Settings icon for that instance (or right-click it in your Library and choose Settings).
Scroll down to Java and Memory Settings and turn on "Custom Java arguments" if it isn't already enabled — this unlocks a per-instance Java Arguments field.
Paste the three arguments from above into the Java Arguments field, then close the settings — the Modrinth App saves automatically.
Press Play. Vulkan should now start correctly. If it still doesn't, use the OpenGL build instead — it needs no extra setup.
Come find us on Discord — the team and community are there and can help you sort it out.