Am I doing something wrong?

Running 2.4.2 on Windows 10. Interface is a Xenyx Q802USB 8 channel mixer, connect to the computer via usb. I have found if I lay one track down, then add a track, record the second track, it picks up the previous track playing and starts to record that on the new track. Of course, I can’t mute the previous track in order to record along with it. Can someone help me please? Thank you.

See here for overdubbing instructions: