After reaching a breakpoint and inspecting your code, it's likely that you'll want to exit from the break mode and continue program execution in some way. You might want to continue program execution, which effectively hands program control back to Unity. This allows the execution to continue as normal, until it meets the next breakpoint, if any. This method effectively resumes execution as normal, and it'll never pause again unless a new breakpoint is encountered. To continue in this way from MonoDevelop, press the F5 key or press the play button from the MonoDevelop toolbar. Otherwise, choose the Continue Debugging option in Run from the MonoDevelop application menu, as shown here:

Exiting the break mode and resuming with Continue Debugging

There are many occasions, however, where you don't want to continue execution in this way. Instead, you want to step execution over the lines of code, line by line, evaluating each line as it progresses...