Most B&R programming is in ST, so all the sample programs and sample function block code snippets have an ST version, and the top of the help tree has [Programming -> Programs -> Structured Text] for a refresher on syntax and available keywords.
ST is Pascal based, but reading through a book about ANSI C would be more helpful than Pascal, especially for B&R. B&R uses some very C-like functionality in their ST (as well as offering programming in ANSI C directly).
You should take the time to learn what a pointer is and how it might be useful. A ton of B&R example code uses `t->.element` pointer dereferencing notation and I remember being a bit lost when I first started out, not even knowing that `t` was a pointer or really what a pointer was.