In his book on Automorphic Forms, Shimura gives (chapter 9) definitions of the the Hecke operators for Shimura curves.
One can give definitions of the Hecke and Atkin-Lehner operators in terms of the moduli interpretation of the curves $X_0(M)$. Shimura curves are of course solutions to a moduli problem. However, I can't find a similar description of the Hecke operators in this case.
$\textbf{Question:}$ Can somebody provide a reference giving a definition of the Hecke operators (in terms of moduli problem) for Shimura curves attached to orders in indefinite quaternion algebras.
(So we can, in particular, calculate the action in finite characteristic.)