If the brake pedal is going to the floor, either you have a leak or the master cylinder is bad. First, here is a link that shows in general how to replace a master cylinder. You can use this as a guide.
Additionally, you will need to bench bleed the new master cylinder prior to installation. Here is a video showing how that is done:
If you look at the attachments below, I included the directions and pictures for replacement specific to your vehicle.
I hope this helps. Let me know if you have other questions.
See pics below.
Images (Click to enlarge)
Friday, April 9th, 2021 AT 9:59 PM