how playstation boot disk work?

i want a modchip for my psone (the smaller, newer version) but no one seems to do them anymore and i dont want to install one myself. ive heard a little about boot disks, where you put some special disk in when it loads up, then take it out and swap it for your copied game.
how do these work exactly and where can i get one?
would i be able to play copied ntsc games on my pal console? (i can already do this on my modded ps2 no problems).
sorry mate, i have no idea what you just said