question about subs

i'm planning on getting a 93 mr2 but its my first car and i 100% sure i want 2 subs preferrably 10's or 15's, most people put them behind the seats but it kinda takes away the leaning space of the seats.

i dont no how to install subs, do they come with instructions? and do all the amplifiers, speakers, coolers and the equalizer that u install in the dash come together? thnx