Well really first step is to download the PIC datasheet on Microchip's website. Then you try to read most part of it.

Read your PBP manual and try the very first LED Blink example.

Attach some push button, LCD or whatever else fancy hardware to your PIC and try the related commands listed in the PBP manuals.

Sure there will be some issues, when it's the case, just paste your code and schematic here and we will help you to understand what happen and why.

Do a search within this frum with PIC16F628, sure enough, youčll find tons of code example as it was, and still, a really popular PIC model.