Typically on one of the knobs there's a depressable button that u press on to remove the handle. Then the plate covering the screws can come off.

Unfortunately, on this one, there is no visible button you can press to remove the handle

Take the knob off, then remove the cover plate and then you will have access to the screw heads

Is there a small set screw on the underside of the knobs?

On one of the shafts of the doorknobs there should be a little hole, using a small screwdriver pop in there and there'll be a pin that releases the doorknob. Pull off the door knob. The cover plate seems to be popped off mostly but you should be able to pull it off now. Then the under screws should be seen and make it where you can unscrew from the door.

This is my main problem, I have no way to take the knob off.

the shiny cover plates are covers, they 'click' on after you screwed it on to the door. The only thing i can not see is: are they removable without removing the knob?

The problem is that there is no visible hole on the shafts of the doorknobs

There are screws under the knob, but you cannot access them without removing the upper part

No, unfortunately they are fixed, they cannot be removed

Well, shucks. Maybes it's just gotta be hammer time!

Put a screw driver between the shiny brass flange ( cover) that is over the hard brass disk. it should pop off and show the screws.

See that little tab that sticks out (visible in the 3rd, 4th and 5th photos in your link) you need to rotate that tab over and then the knob can be pulled off, once the knob is off, remove the collar that covers the screws to remove the knobs.

You need to rotate the locking tab that holds the knob on first.

There should be a really small set screw on the knob

Or the knob my unscrew

This man doorknobs.

Hack saw

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