I'll warn you that Picat is very much a "research language" and a lot of the affordances you'd expect with a polished PL just aren't there yet. There's also this really great "field notes" repo from another person who learned it: https://github.com/dsagman/picat
Side note: Just clocked your name. Read through Practical TLA+ recently modeling a few things at work. Incredibly helpful book for working through my first concrete model in practice.