Some squirrel resources for you:
https://squirreltunnel.com/ if you locate a point of ingress that you can't block off like an air vent, but don't want squirrels using it
https://ruggedranch.net/catch-mor-traps/ if a Havahart won't cut it for you.
https://mousetrapmonday.com/videos/t...setrap-monday/
As for baits, I use peanuts in the shell but occasionally have to switch it up to sunflower seeds or peanut butter on an old plastic container lid.