With calipers, measure the width of each end of the pin. You want to find the smaller of the two ends. The smaller the pin, the more difficult this is.

On my machine, the smaller pins had one end ground flush to the part, and the other sticking out. The end that stuck out was the smaller end.

Many of the larger taper pins have a rounded end and a flat end. The rounded end is the larger end.

Position the part in the arbor press so that the part is supported by the jig you made, and the small end of the pin is up.

Press on the pin with the arbor press. If you are close to using all of your strength and the pin has still not moved, give it a few more heat - lubricant cycles.

If the thing still doesn't move, you may be pressing on the wrong end. In which case, see the next step.