I have it set up to print st and ct (both done by Dom Pothier in his earlier typesetting adventures)
%%% FONT %%%
\usepackage{fontspec}
\setmainfont{EB Garamond}[UprightFont=EB Garamond Regular,
ItalicFont= EB Garamond Italic,
BoldFont= EB Garamond Bold,
Ligatures=Rare,
Numbers=Proportional,
Numbers=OldStyle]
The syntax is a little odd because the EB Garamond font has some issues, and because I also have it installed on my machine. LaTeX finds it there, not in the package ebgaramond. (Which means that I struggle to find the medium weight of the typeface which is a bit annoying). Anyway, I hope that this is a good start. Do check the fontspec documentation, and if you get stuck, TeXSE is a good landing spot for questions.