Well Betwixt went to great lengths to explain Bootstaps / Bootloader ( same thing) to you yesterday.
The PIc16Bootloader site does explain how it all works, but it does need the Bootloader program to be programmed into the 877a chip by a conventional programmer fisrt.
Once that is done then you can downoad your operational program code by means of the booloader program / the RS232 PC Link.
I assume you think you can use the Bootloader method to avoid using a conventional programmer - well you can but only after programming the Bootloader in first.
So as you can see you need access to a conventional programmer regardless, so if you have one why bother with bootloaders which just add another layer of software and hardware - as you are clearly struggling to follow things why not take the easier conventional programmer route for now.
( thought I better reply here before Millwood sees it and starts having siezures :wink