how do i fix my brakes on a 89 honda accord dx

Sounds like you have air in the system, I would have the brakes bleed as a FYI air just doesn't get into the system, there may be a leak letting air into the system. Don't drive the car until you have it checked out..

Where can I get instructions on how to bleed the brakes

Here are a couple of you tube that will help understand how to do it. https://www.youtube.com/watch?v=lPwM2vn3bT0 https://www.youtube.com/watch?v=zoewhwUu3UQ https://www.youtube.com/watch?v=hB3T_JwB8fM

Do I need a power bleeder

A brake bleeder is a handy one man device to change the hydraulic fluid in your car. Using either pressure at the reservoir or vacuum at the bleed nipple, turns this fiddly chore into a one man operation, removing the need to have someone in the drivers seat pumping the brake pedal, with all the shouting that accompanies it.

What if there is no air

There has to be air in the system if the brakes are going all the way to the floor, you can't compress hydraulic fluid. just make sure you following the directions on bleeding the brakes I sent, make sure you don't let the master cylinder go dry always keep it full while you a bleeding brakes

You can have a bad master cylinder and it will act like there is air in the line.

Did you have a brake job done when this started to happen ?

There are 3 reasons your pedal would go to the floor. First if you you had brake work done that they needed to replace a part like a brake hose , caliper , etc you would have to bleed the brakes . Second if you look into your master cylinder and the brake fluid is low or none at all leak needs to be found and repaired then bleed brakes . Third if you look into your master cylinder and there is still brake fluid in it most likely your master brake cylinder. You can tell if it is the master cylinder there would be brake fluid running down the back between the master cylinder and brake booster.