How to debug in this case?

Question

Debugging

there is a project. it is large, the code is divided into lib files, which are collected in one executable during compilation, and in general it is a program with a graphical interface. I need to debug one function. but I don't understand how to do it. this function is located just in lib. I set a breakpoint on it, start debugging step by step, and the studio writes that hitting the breakpoint will not happen. that's how it happens. I use visual studio