2 wired doorbells, 2 existing chimes in home

Hi, I purchased 2 of the newest wired doorbells and the set up instructions seem straightforward but I have 2 existing doorbell chimes in my home and it’s causing confusion. One is located upstairs and the other is in our basement so you can hear the doorbell chime down there as well. The directions show to use the jumper cable that comes with the doorbell but I cannot find any other information as to what to do if there is a second chime from the old doorbell. Should I be using a jumper cable on both? Also, why do we use the jumper cable on the existing chimes when they won’t notify us and hve to buy a Ring Chime?