It's not that hard. You would set the taper attachment at 1.4307 degrees for a #2 taper and 1.4377 degrees for a #3 taper to begin.
Start with a piece of metal a little longer than you will need. That way you can machine and measure, then make a slight adjustment
to the taper and machine again. The extra length will give you the extra material you need for a few test cuts. You can always
cut off any excess when you are done. You can test fit in a female taper using some Dykem when you get close. A file is handy
to take a little off the high areas and setting a flat stone on all the taper while rotating will show the high spots that wear off the Dykem.
It is somewhat of a trial and error thing as a lathe will get it close but one has to fine tune a bit to get it close to perfect.
I used the information on "Little Machine Shop" to find the angle to set the taper. Also there is other helpful information
on the site to help you get the job done like taper per inch, length of taper, total length etc. It's very handy to have enough information.