here, take a look at these, they were made by me, it should give you a pretty good and easy to understand example of how to use natives
http://www58.zippyshare.com/v/95268474/file.html
http://www8.zippyshare.com/v/89443802/file.html
then in main plugin that needs to open cells, just jail_open
when creating the .inc file you don't need to pay much attention, I just replace everything that needs to be replaced with correct file names, so
Code:
#if defined _jail_open_api_included
#endinput
#endif
#define _jail_open_api_included
//replace with kz_main or what your plugin name is
//same goes for these
#pragma loadlib jail_open_api
#endif
#else
#pragma library jail_open_api
#endif
#include <cstrike>
//commands that are natives
native jail_open()
native jail_close()
I wrote this because it's probably the part that will confuse you