Noisy spin cycle in Maytag topload washer mav5000aww?

During the spin cycles for drainage/rinsing, my washer recently began to make a loud rattling/grinding noise, most prominently near the bottom of the washer. A couple of taps/fist pounds at the front/bottom of the washer seems to have a temporary affect of changing or diminishing the noise. I've tried to move the basket all around in an attempt to dislodge anything that might be stuck along the side (bra underwires, etc), but the noise persists. I'd like to know how to safely open the machine up (and close it when done) to look inside for a possible foreign object and to evaluate the motor/drive/belt, etc. I'm a first-timer for this, so the more detail the better. I'm pretty handy with most things, so I'm looking forward to this challenge.