Resources for implementing dependent type theory
This paper is my go-to for implementing dependent types. It starts from the basics, uses bidirectional types, and has accompanying code in Haskell.
If you're at all interested in type inference, this paper is great, and also has accompanying Haskell code.
David Christiansen has a tutorial on dependent type checking with bidirectional types, with a Haskell and Racket. More generally, I've heard great things about his book The Little Typer, though I haven't had a chance to read it myself.
I've heard great things about  smaltt  by András Kovács, particularly for it being an efficient implementation.