par rate vs ytm vs coupon rate vs spot rate

I am so confused by all these in fixed income section questions

so i understand the test would want us to convert the various rates to spot rate, and par rate is the same as YTM when the coupon is priced at par

I am confused by the so called calibrate process mentioned in reading 44 in EOC and do how is coupon rate used differently from the par rate, i just use everything as par rate…

Can someone go into detail on this?

I wrote an article on creating a binimial interest rate tree that may be of some help here:

You need to be aware that the coupon rate on a bond is independent of the YTM (the _ par _ rate) on that bond. If company XYZ issues a 5% coupon bond selling at a YTM of 8.5%, and they issue another bond (of equal seniority) with a 15% coupon, it, too, will sell at a YTM of 8.5%. The market has decided that XYZ bonds require a return of 8.5%, irrespective of the coupon they pay.